I use the Pro version of outpost firewall but im not to sure with the free version of outpost as its a suite and the av parts have to be disabled but mainly you should only have to check that in the applications list of outpost that all the avast processes are set to allow all and for the avast file system shield you can add the outpost program file to the exclusions list, there is actually only one DLL file of outpost that needs to be excluded in avast but i cant remember what it is, DavidR would know so for now you can just add the program file.
As Bob stated ABP stands for adblock plus which can be added through manage addons-tracking protection-get a tracking protection list online, there are two easylist addons to be added and these stop 99% of the adds being displayed when im browsing and give the obvious ( tracking protection ).