I did a bit of work updating the project files for the SDK (Software Development Kit). This was largely motivated by getting your code to compile using the existing projects, rather than using a copy of the source files. I then updated your project to depend on the existing SDK projects, and removed the duplicated code. This makes for a much cleaner project, and is now much easier to see what code is yours.
I've also added a Post-Build Event that copies the compiled level DLL to the game folder. (I removed your project settings that placed the DLL file in the project root).
To make testing easier, you can set the Debugging Command to point to Outpost2.exe, which lets you run Outpost2 from Visual Studio. Just press Ctrl+F5 to run (or just F5 to debug, which means run with a debugger attached).
Project -> Properties -> Configuration Properties -> Debugging -> Command: ../../../../GameDownload/Outpost2/trunk/Outpost2.exe
(Assuming you want to run your code using the copy of the game in SVN, which is quite convenient for development).
I would have added the debugging command to the project file in SVN, but I found out it's a user specific option, and user specific files usually aren't checked in. I currently have a global SVN ignore for such files. I'll have to think about this a little more, since that used to be set in the old Visual Studio 6 project files.
I haven't actually played around with the Earthworker problem yet. I'd like to "reduce" (gut) your project until it has the minimum amount of code needed to reproduce the issue. It might be nice if you took a look at it in it's current form, before being gutted. I'd like your feedback on the current project organization. I'd like to know if you find it clear and easy to work with.
Also, I would encourage you to actively develop your project with the code stored in SVN. A more suitable place for actual level development (as opposed to bug hunting) would be in the "Levels" folder. (outpost2/LevelsAndMods/trunk/Levels/Ravine). This would be a great chance to practice an "SVN copy". What you can do, is run an SVN update to download my changes, check it out, see if you like them, and if so, you can right-click drag the Ravine folder from the BugReproducer folder over to the Levels folder. When you let go of the right mouse button, a menu will pop-up, and you can select "SVN Copy versioned items here". Then you just commit from the new location, and add a log message. (The copy means the repository doesn't need to store a second copy of the files, it will just refer to the already committed ones).