I think cob only supports DOS 8-character filenames (so does 3ds, natch), so you may find that where it should reference the likes of capital01t-01 it references capit~01 or similar. Um... also, I don't think cob supports PCX, not sure, but by default pofs only use PCX files; I'm not sure of the pof->cob convertor also changes the references to bmp files when converting back; certainly the cob->pof convertors had the cob using bmp files without problems. (actually, I have a feeling the extension isn't stored in the pof file, just the filename, as FS2 knows what extensions it can and can't look for)