Conflicting addon CABuildings in 'gsfbase\buildings\', previous definition in 'ca\buildings\'
All the PBO's you UNPBO'ed should be in;
P:\CA
Not in your gsfbase directory
Only YOUR project should be in gsfbase
All BIS buildings directories etc need to be in the CA directory in P drive
i.e. In P:\CA you should have many other directories, like "buildings", "rocks", "roads" etc, each corresponding to a PBO you Un-PBO'ed
Be careful with ROADS, don't overwrite the MLOD files in there that the tools installed for you already.
Unfortunately you will likely have to delete all buildings you added to your map and start again.