attempted rmdir with cron job

Every time my cron job runs I get the following errors:
First --
warning: rmdir(misc/fscache//A9): Directory not empty in /home/dajudge2/public_html/dr/main/modules/fscache.module on line 368.

Then --
warning: rmdir(misc/fscache//A9/FD): Permission denied in /home/dajudge2/public_html/dr/main/modules/fscache.module on line 368.

That directory (and I don't understand the // ) IS in fact empty. I'm tempted to just delete the directory but since I don't understand how fscache works, I don't know but what that emptry directory actually serves a purpose.

The code starting at line 368 is:
function _fscache_generate_cache_name($offset = 0) {

$fname = strtoupper(dechex(time()+$offset));
$fname = strrev($fname);

return $fname;
}

What to do?

gil