I sometomes have the same problem EXPORTING some daz figures to an obj.
 belive that it has to be with corrupt files, since cr2 and obj files are just plain text is easy for them to corrupt. I'm only especulating here but, to be on the safe side I make backups of those files
also remember to DEFRAG your HD!!!!!!!!!!!
it's the first source of problems and the solution of some...

hoped to help
Jason Blood