[TYPO3] CoolUri Warning: mysql_fetch_assoc()

[micho edo]

Using CoolUri I get the Warning:

Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL 
result resource in 
C:\bin\TYPO3_4.1.6\htdocs\coolUriTest\t3lib\class.t3lib_db.php on line 796

what´s the reason for this?