Corrupt itunes library file

So the library file for my itunes dumped everything. The files are fine and I reimported them and the computer created a new library file. When I closed and reopened itunes again it came up as corrupt and dumped everything again. Is there someway to keep it from coming up corrupt when itunes opens?
I have also have had problems syncing my ipod after I reimport everything.
Very open to suggestions. Thanks in advance.

Its a Mac-- I consolidated last night and but the one thing I failed to mention was that the music was on an external drive. It works again, but its back on the hard drive and I have no disk space left.
So I may just start over, dump what is on the external and see if it works the second time. Thanks for the help.