Because the zombies arent safe 
AFAIK nightly builds are not code-signed by Mozilla so no chance CIS can flag this āSafeā unless you wish to pile up the safe-database with all nightly build hashes from all popular applicationsā¦
sorry guys I canāt test it, I tired but could not get office 2003 to install on my vm. hopefully egeman comes in with the answer. ;D
Topic Hijack.
CCC (Catalyst Control Center) has always two executables that get sandboxed after each update. Ronny already commented on nightly builds.
What makes you think skypekit is a safe application according to Comodo? Did you ever submit it?
I cannot comment on Left 4 Dead 2. Try submitting it in White listing Games to get it whitelisted.
Not only are you hijacking a topic but suggesting nightly builds should be deemed safe by Comodo shows that you are ill informed. The analysis speed for white listing simply cannot keep up with the that of nightly builds. Further one could wonder if white listing test builds is a useful thing in its self.
Please start your own topic when needed or submit files to be whitelisted.
Maybe defining CCC as installer/updater in D+ could solve the problem?