An Ubuntu security feature introduced at 10.10 which is intended to prevent process hijacking can interfere with debugging. Here is the post:

https://wiki.ubuntu.com/SecurityTeam...e%20Protection

This ptrace protection prevents attaching to a running process and can affect
ReplayEngine. A short term fix is to become root and do

“echo 0 > /proc/sys/kernel/yama/ptrace_scope”

Pete Thompson
TotalView Customer Services