Gomtuu

I just had the same problem, after poking around a bit I fixed it by editing the settings of FOMM (I could only reach them by starting Advanced setup). I changed the mod and install info directories and after that I could start FOMM. I couldn't click OK after changing the settings, but simply closing the window seemed to have done the trick. I think it crashes because it fails to read the files in those directories, and I assume you have installed mods already, I at least have.