Mapped Drive issue

["Rob Kritzer" <gdmfer@xxxxxxxxx>]

I have a script the use to work:

$date = date("mdy");

mkdir("Y:/Daily_DisplayAds/todays_ads-$date");

But now I get this error:

Warning: mkdir() [function.mkdir]: No such file or directory in
C:\wamp\www\scripts\ad_finder\display_class.php on line 10

If I change "Y" to "C" it works, can anyone please help me thanks.