If it is this UKF Weapons Pack
you trying to use, you wont be able to as its for ArmA II Operation Arrowhead (Note: It says Requirements: Community Based Addons)
You might want to try this UKF Weapons Pack
or this UKF Weapon Pack
instead, both require Community Based Addons.
It might be easier well less work needed to get operation arrowhead and the BAF dlc ;)
You say this is for ArmA II, so please post this thread in the right topic, this is the Operation Arrowhead topic. Topic shall be moved.