Weird, weird, weird!

Anyone ever have the experience of working on a site, working with MySQL and then having something almost inexplicable happen? I was working on a script, and had this weird event. A very simple script with this: mysql_connect("localhost","user","pass"); mysql_select_db("dbname") or die("Query Connection Database failed"); $old=date("z")-1; mysql_query("DELETE FROM Users WHERE Date < $old"); $cartquery = mysql_query("SELECT CartItemsID,Date FROM CartItems") or die("Query failed"); $cartnow = mysql_query($cartquery); $cr=0; $cartme = mysql_num_rows($cartnow); <<<<this is the line that is failing! while ($cr < $cartme){ $cartrow=mysql_fetch_row($cartnow); $CII=$cartrow[0]; $CDa=$cartrow[1]; $pieces=explode(":",$CDa); $DCHK=$pieces[1]; if ($DCHK < $old) { mysql_query("DELETE FROM CartItems WHERE CartItemsID = '$CII'"); } } Started spitting this error at me: Warning: Supplied argument is not a valid MySQL result resource in (exact location snipped) This is the line containing mysql_num_rows that is getting this error. Someone please tell me I'm missing something obvious! Yes, the connects to MySQL database are fine. I can run the query right in phpMyAdmin with no issues. If mysql_num_rows returns 0, or empty, it shouldn't be complaining, should it? It would just skip the loop, correct? Thanks, -Mike