Lpc2000

I am trying to recieve messages on LPC2129 with Extended 
Identifiers.The sample code given in the files works well for normal
identifiers but when i tried to recieve Extended Identifiers over 
CAN  my C1RID field reads as 0x00 or 0xFF
i already set the CIRFS register with proper value but its still not
reading the identifier field proerply.Has anyone faced a similar 
problem......im open to all suggestions.

		 C1RFS = 0X80080400;
Regards
Micheal