Comment 9 for bug 1052098

BLOCK_SUSPEND is a capability in newer kernels. 'deny capability block_suspend,' is found in the 12.10 CUPS profile, which is fine since the 12.10 kernel has it and the apparmor userspace for 12.10 was compiled against the 12.10 kernel headers. However, on 12.04 the apparmor userspace was compiled with older headers and so it doesn't understand this rule.

tlu, what version of cups are you using? Can you give the output of:
$ apt-cache policy cups