I can't reproduce your problem, so I don't know if this will work, but it's worth a shot
CORE: Returns a representation of PATHNAME composed of longname components (if any). The result may not necessarily be longer than PATHNAME. No attempt is made to convert PATHNAME to the absolute path. Compare with Win32::GetShortPathName() and Win32::GetFullPathName().
This function may return the pathname in Unicode if it cannot be represented in the system codepage. Use Win32::GetANSIPathName() before passing the path to a system call or another program.