The panic message you printed reports an error in File::Basename, but you should also indicate the version number of perl, and where you got it

  perl -V
[download]

output would be valuable.
As others have said, the function XMLin is not part of the core perl, so it is very difficult for anyone to reproduce the problem without more information. Do you think you could reproduce the problem without XMLin? (obviously, there must be some other code that you didn't reproduce in your post, right :-)