more error checking, don't try to convert the file if it does not exist.
more error checking, don't try to convert the file if it does not exist.


git-svn-id: 28d9401aa571d5108e51b194aae6f24ca5964c06@5428 8cc4aa7f-3514-0410-904f-f2cc9021211c

crystalspace/CS,crystalspace/CS,crystalspace/CS,crystalspace/CS,crystalspace/CS,crystalspace/CS,crystalspace/CS,crystalspace/CS