I use Task Scheduler at home with a daily scheduled task, and it works fine for me. Since you give my few details, it's hard to guess what's going wrong, but the things I would look at:

• Task Scheduler: Last Run Result => should give exit status for the last run
• In the Actions | Edit Action dialog:
  • "Program/Script:" c:\full\path\to\perl.exe = Task Scheduler doesn't necessarily know the PATHs you think it does
  • "Add arguments (optional):" to c:\full\path\to\script\filename.pl = Task Scheduler needs to know where the script lives
  • "Start In (optional):" to c:\full\path\to\script = If this is skipped, relative paths in your script won't be relative to your filename.pl's location
• If that wasn't enough, use error logging to a hardcoded file (open my $fh, '>', '' or die $!; ... print $fh "messages\n"; ...) or using Log::Any, or redirect STDERR (look in open and search for "redirect"), which will get error messages to a known location, so you can figure out what's going on.

The more details you provide, the better we can help you: see I know what I mean. Why don't you? and SSCCE

update 1: fixed typo: s/my/few; thanks LanX