I assume by "build 638" you mean that you are using ActivePerl, but Win32 could mean any of several versions of Windows; it would really help if you specified the exact versions.

Incidentally... Perl 5.6.1 was released in April 2001, and Windows XP (which is currently the last fully supported version of Windows) was released after that, sometime in October 2001. You might want to try a later version of Perl, partly to see if the bug is fixed, and partly because you are running without quite a few subsequent security patches.