Ok damein, through the settings of BufferZone disable its automatic firewall and disable it from startup. Reboot. Now install CIS. After that add bufferzone to trusted files of Defense+. Switch on BufferZone and in its exclusions put Comodo IS. Thats it and re-enable its autostartup. I too use the same combo. I use CIS Pro and BufferZone Pro.

---------- Post added at 05:24 PM ---------- Previous post was at 05:22 PM ----------

Damien, for your question about BufferZones firewall let me clarify that the firewall component auto sandboxes unknown softwares. I personally use BuffferZone only when needed, as even comodo auto sandboxes unknown programs so it is a overkill.