deadpickle's path appears well formed, meaning he knows how to escape slashes, so forward slashes aren't needed.
Usually you want to know why unlink failed (and on what line)
my $filename = qw[ C:\Users\deadpickle\Desktop\UAS\GRRUVI_1.60\panel\U
unlink $filename or die "Couldn't unlink($filename) : ($!)($^E)";
+1) : (No such file or directory)(The system cannot find the path spec
+ified) at - line 2.