author: DaBDouB-MoSiKaR [Moroccan Security Team]
site: www.o2php.com 
greetz to : [Moroccan Security Team] CiM-TeaM and All Freinds
Solution: intval()
exemple:
http://[target]/post.php?action=newthread&fid=[sql] 
inbox:DaBDouB-MoSiKaR[at]moroccan-security[dot]com