The problem is that you're creating directories with:

mkdir "trip", 077;

You most likely wanted 0777, or you can omit the mask parameter completely and Perl will do the right thing for you :-)

Moreover, a quick inspection of @files revealed the other possible problem: the special directories . and .. are included in the array, and your script is trying to rename them as well. I couldn't test it on Windows (using Linux here) but it should be the same.

Update: mentioned that @files contains . and ..