Is there perhaps some code around this that you are not showing to us? I tried your example on Perl 5.10.0 and it ran fine for me:

>type \help\perlscripts\test2.dat
C:\HELP\Docs\R2009\sp01\

>dir C:\HELP\Docs\R2009\sp01\
 Volume in drive C has no label.
 Volume Serial Number is 74E6-4409

 Directory of C:\HELP\Docs\R2009\sp01

09/25/2009  09:57 AM    <DIR>          .
09/25/2009  09:57 AM    <DIR>          ..
               0 File(s)              0 bytes
               2 Dir(s)  224,589,967,360 bytes free

>perl pathq.pl
Found C:\HELP\Docs\R2009\sp01\

>perl -v

This is perl, v5.10.0 built for MSWin32-x86-multi-thread
[download]