I'm assuming that JCreator was created using Visual C++ 2005 with .NET 2.0. Just recompile it using DotGNU or Mono (.NET for Linux) and you're done. You might consider using MinGW to get the whole project over to Open Source compilers. If you do that, then you could do a simple recompile so it'd work on Windows, Linux, Solaris, and OS X. Why? DotGNU/Mono is cross-platform. It works on Windows, Linux, Solaris, and OS X.
In addition to that, you could leverage advanced scripts which would allow you to remotely build the project whenever a new version is checked into version control and put it on the local LAN/WAN/WLAN for testing. No human required.
Oh, and the whole setup is free:
- Bloodshed.net's Dev C++: $0
- GNU Compiler Collection v4: $0
- DotGNU/Mono: $0/$0
- Quadrupling your list of supported platforms: Priceless
There are some things money can't buy. For everything else, there's FLOSS.
Note that none of this would necessitate making JCreator Open Source. It could remain closed-source and maintain total legality. The GPL will NOT kill you. Proof? OS X is built using GCC. You have to pay for OS X.