Usable Vectors

I'm getting an error message that reads:
"No usable vector paths in this file." which I would normally understand, but not for this one. I have about 60 paths in this AI file. Using certain combinations of paths works fine, others don't. For example, using paths 1-10 imports fine, but adding path 11 or 12 gives the error. But using path 7-12 imports fine. So it doesn't seem to be that paths 11 or 12 are broken, but that Invig can't combine them with certain other paths. Any ideas on what might be happening here? Thanks.