We're not talking about FS2, we're talking about TBP. TBP installs itself to the c:\Program Files\ directory, then \The Babylon Poject\data etc. It seems that the "Program Files" part of the entire command line would seem to be causing the problem. If I use the "Mod" option in this or the 5.2 launcher, and try to select the mod directory (which, for reasons of secrecy shall remain nameless, but contains no spaces), it says that the mod directory cannot contain spaces. As I said, removing the spaces in "The Babylon Project" didn't help, n'or did changing the name of my mod directory to something longer incase there is a minimum name length for mod directory names, so I can only assume that the "Program Files" part is the problem.