sounds great i will be checking this out in the future for sure! hope this works as it should and good luck!

Programmer to Programmer, let me say your framework is setup nicely.
However, as of right now, the project you posted for download has files linked outside. Your app crashes because of the missing files. Always test your project on another machine before submitting executable/binaries code.

The missing files are icon files...
~C:\Documents and Settings\icons\class.ico
~C:\Documents and Settings\icons\tree.ico
~C:\Documents and Settings\icons\folderclosed.ico
~C:\Documents and Settings\icons\folderopen.ico


Since I didn't have these files I replaced them with my own icons, to see your app. I'll be watching your progress. I'm developing a Game Engine as well, pretty much the same concept as yours, just on a smaller scale.

Good Luck

After further testing... The scripts files to save data are missing from that directory as well...

Pass a command to create if doesn't exist or using try/catch exception to ask the user if they would like to save it there or elsewhere.