Arctic Cooler Freezer 7 Pro v2 AMD mount problem

Hi all

Mobo: GA-MA770-UD3 rev 2.0
CPU: Phenom ii x2 550 BE

finished my first build yesterday, but had to swap for the stock HSF  

Wondering if anyone else had a similar problem before...

Basically when I lower the hsf down on top of the CPUs, its pretty much impossible to fasten the screws into the latches, the gap is too far for them to reach, any had this problem before? I'm pretty sure the fan is meant to be compatible with AM2+ boards

the current stock HSF sounds like a power station too, could this be too be installing it wrong? even when im not doing anything very taxing

thanks