I found out that the program is attempting to rename RO.DAT as RO.EXE and back again. It does not appear to be write protected but perhaps Windows 7 has some new feature which is preventing this. I can manually change the DAT to EXE but the game will only work once as the code within the game itself automatically attempts to change EXE back to DAT. Although it won't let this happen, the EXE file becomes corrupt!!!