Hello,
What version of SEP 11.x are you carrying?
Secondly, what version of Liveupdate was installed on the SEP client machine (to check, open the Add/ Rremove Programs)
I see no reason, there is a Conflict between Liveupdate, SEP and Quicktime.
Again, as I see this should not be happening on all machines.
Is this issue happening on multiple machines?