First: Being able to do something from the command line doesn't prove that it isn't a file permissions issue. As someone else has already pointed out, web server's run as different users and therefore with different permissions.

And B: Print an error message if you can't delete so you get an idea of what happened.
unlink($ful) or die "Unable to delete [$ful] : $!";
I usually put variable names inside some type of enclosure, like brackets or braces so that if there is an extra newline or something, you'll see it on the screen when the error prints.