I've found out that the following file is essential for running the game on my PC:

Microsoft Games for Windows - LIVE Redistributable v1.2
http://www.microsoft.com/downloads/details.aspx?FamilyID=d6a69b9f-2aef-4125-b162-edf0ae922caf&DisplayLang=en

If everything previously said fails, then I recommend trying to download and install this file.

Shining Force 2 Remake
Demo version 0.1.1

Requirements:
The game is programmed using XNA Game Studio, so you need to download and install some additional files to run it.

If you use Windows XP, these files are:
DirectX 9.0c: http://www.microsoft.com/downloads/details.aspx?FamilyID=2da43d38-db71-4c1b-bc6a-9b6652cd92a3&DisplayLang=en
.NET Framework 2.0 Redistributable: http://go.microsoft.com/fwlink/?LinkID=76064
.NET 2.0 Servicepack 1: http://www.microsoft.com/downloads/details.aspx?FamilyID=15fb9169-4a25-4dca-bf40-9c497568f102&displaylang=en
XNA Framework Redistributable: http://go.microsoft.com/fwlink/?LinkID=78244

If you use Windows Vista, these files are:
DirectX 9.0c: http://www.microsoft.com/downloads/details.aspx?FamilyID=2da43d38-db71-4c1b-bc6a-9b6652cd92a3&DisplayLang=en
.NET Framework 3.5: http://www.microsoft.com/downloads/details.aspx?FamilyID=333325fd-ae52-4e35-b531-508d977d32a6&DisplayLang=en
XNA Framework Redistributable: http://go.microsoft.com/fwlink/?LinkID=78244

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These are the recommendations I got from the people at creators.xna.com. Please try if it leads to success.

I'm using C#. C# is a language developed by Microsoft for their .NET platform. It is based on C++, Java, SQL and Delphi. Like C++ and Java, it is object-oriented. The differences to C and C++ can be found here: http://en.wikipedia.org/wiki/C_Sharp_(programming_language)#Features

I enjoy programming in C#. I learned C when I was 11 years old and thus know the syntax of C very well. C# has some features which make it easier to program in than in C. Moreover, C# is the language for which the XNA Game Studio has been developed to run with, which I'm currently using as it simplifies some essential things about game programming. But XNA has also big disadvantages such as a lack of portability and compatibility problems, so I'm considering to abandon it. Even if I won't use XNA in the future, I'll stay with C# as it has proven to be very effective.

Regarding the path finding algorithm: It isn't too difficult to implement IMHO. Just implement a depth-first search that tries all possible movements until the target position is reached, then save the path, continue searching for a path that is shorter than this one, and so on. With current CPUs, this algorithm is fast enough. Especially as the characters only have a movement range of less than 10 steps anyway.

The following things come in my mind:

* Battles
  * Support/Status effects
    * "BOOST" spell
    * "SLOW" spell
    * "SLEEP" spell
  * Darkness (e.g. in caves)

At http://forums.xna.com/forums/t/1988.aspx they write that the following files must be installed in order to be able to run XNA based games:

   1.  .Net 2.0 PLUS the C++ 2005 SP1 Redist -OR- .Net 2.0 SP1
      Some notes on these dependencies:
          * .Net 2.0 comes already installed on Vista RTM so you only need the C++ Redist for vista machines
          * .Net 2.0 SP1 will not install on Vista RTM - you must install it by installing either Vista SP1 or .Net 3.5
          * You may have either of these 2 already installed from such places as Visual Studio SP1 or Games For Windows Live but don't rely on other places if you are writing an installer.
   2. DirectX9.0c *See note below
   3. XNA runtime 2.0
   4. For games that create a GamerServicesComponent/use live networking - REQUIRES a full Game Studio 2.0 install, the G4WL redist is NOT sufficient since there are non-redistributable components in GSE 2.0 that are required.  This will also satisfy the VC++ 2005 SP1 redist requirement, you don't need both.

Elvenfyre: Is DirectX 9.0c installed on your laptop?

That's bad news. I'll continue asking in the creators.xna.com forum, maybe one day we will ultimately find out what is missing. In any case, it's a big disadvantage of XNA that it's not simply possible to download the game, unpack and run it. Maybe I'll try to recode the game without XNA. The advantages of XNA are that synchronization is very easy to achieve and it has powerful routines for sprite handling and other essential things. But it's possible to code these things oneself, it's just more difficult.

OK. I'm curious if it will work on your laptop, too, if you install the .Net 2.0 servicepack 1 as I mentioned in my private message to you. If it works, then I'll update the readme.txt so that it will mention the three files and hope that these three files will make it work for everybody.

I'm planning to include every function of the game, save & quit too. My dream is to make a complete remake of Shining Force 2 except the scenes in between the battles (instead I will probably just include textual summaries of the storyline, similar to Shining Force Gaiden/CD). I'll do this in my sparetime in the next months/years if God wills. What you can currently see took me about half a year of programming.

I also have several ideas how Shining Force could be improved - if somebody could help me with the graphics and music, I'd like to create a completely new game based on my code.

Yes, it works on this PC if the whole XNA Game Studio 2.0 is installed.

So, the solution is:
1. Download and install Visual Studio C# 2008 Express Edition: http://www.microsoft.com/express/download/#webInstall
2. Download and install XNA Game Studio 2.0: http://www.microsoft.com/downloads/details.aspx?familyid=df80d533-ba87-40b4-abe2-1ef12ea506b7&displaylang=en

It's a big download, so I'm not satisfied with this solution. One can't demand from every gamer to download a full programming language and a framework. Therefore I've asked on the Microsoft XNA forum if anybody knows a better solution.

It's Microsoft's fault: Their Microsoft XNA Framework Redistributable 2.0 is buggy. :-( I wonder why apparently nobody else has yet had this problem and this hasn't been fixed yet?

With the debugger I got to this:

LDR: LdrpWalkImportDescriptor() failed to probe C:\Windows\assembly\GAC_32\Microsoft.Xna.Framework\2.0.0.0__6d5c3888ef60e27d\Microsoft.Xna.Framework.dll for its manifest, ntstatus 0xc0150002
(e70.f08): C++ EH exception - code e06d7363 (first chance)

So the problem definitely is with the XNA Framework and not with my code. The reason why it works on the PC I developed may be that on this PC there's the complete XNA SDK installed, while on the PC where it doesn't work only the runtime is installed. I'll try what installing the SDK on the problem PC will result in.

It works on the PC on which I've programmed it (Windows XP Service Pack 2). That was the only PC on which I tested it until today. Now I've tested it on a Vista box, and it doesn't work. I immediately get a window that reports that the "application doesn't work any longer". It seems to be a problem related either to the Microsoft XNA Game Studio 2.0 or to Microsoft Visual Studio 2005, with which I programmed the game, not to my code, because I tried another game programmed with these environments and it resulted in a crash, too. Well, I'll try to find out what causes the crash on this PC. If I find it and manage to fix it, maybe it will then work on your PCs, too. I've searched for the error code on the web and found something, now I'll try a debugging tool to find it more.

I followed the instructions and downloaded the necessary packages, installed them and restarted.
I get a windows(xp) error telling me it has encountered a problem and the program doesn't start. 

That sucks! Such an error message should only appear if the necessary packages have not been installed. I guess you've rebooted the computer after installing the packages. In that case it ought to be working. I don't know why it's not working.

Is anybody else experiencing this problem or is it working on everybody else's PCS?

I'd be happy to privately send you the error report for windows if that would help you at all.

Yes, please send it to me. Maybe it will tell me something.

That would be extremely cool! If you need somewhere to host the download, let me know and I'll sort it out

That would be great. Currently it's 12 MB zip-packed (mostly due to the soundtrack being WAV, perhaps I'll find a way to transform it to a more compact format such as MP3).

I'm working on a remake of Shining Force II... not 3D though, but close to the original game. It's already possible to play a full battle from the original game. Maybe I should make a demo version available for download?

Well, thanks. I'll try it using the White Ring. The only other ways of preventing that the healer gets affected by demon breath are HEAL 3 and AURA, which take a lot of MPs.