Added a couple of checks that should have been in place to avoid bad length calculations.
Added a couple of checks that should have been in place to avoid bad length calculations.


git-svn-id: 28d9401aa571d5108e51b194aae6f24ca5964c06@21688 8cc4aa7f-3514-0410-904f-f2cc9021211c

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