Interaction with Skipe

I’m a Skype user and noticed a different behaviour running COMODO Firewall under Vista or XP.I have 2 installations of Firewall,both of the latest version 4 now;one is under Vista HP SP2,the other one under XPPro SP3;in both systems Skype V4.2 is installed (it was V4.1 before);the problem is the following:
with XP,upon starting Skype,Def+ detects some “suspicious attempts” to access memory,coming by Skype.exe,target cmdagent.exe and cmp.exe,and blocks said activity.With Vista nothing happens,no “suspicious attempt” detected.Settings are same for both the installations,actually the default ones (memory access protection active for CIS apps and Skype “trusted”);furthermore,Skype seems running and working properly even with these activities blocked.
My question is this:what can happen if Skype enters the memory of those apps?
Hope somebody has some idea about this strange behaviour;thanks to everybody.

I suppose Skype is wicked app like many other free apps