[nsp] Cisco problem

[Kevin]

I have an 7513 router with RSP4s,
I tried upgrading the IOS to 12.3(1a) and 12.2(14)S3 to fix the DDOS vulnerability.
I have 3 Serial interfaces ppp mutilinkd to one of my upstream providers,
Before I was running 12.1(14).
Anyways after upgraded if I enable IP CEF the multilink interface does'nt allow any packets 
To go through, pings, bgp packets, nothing, but If I disable ip cef everything works fine.
Although with 12.2 I was able to send some packets through although with heavy packet loss,
The Multilink interface shows up and now errors when CEF is enabled.
Has anyone experienced this before?

Kevin,
Honeycomb Internet Services