Water cooling - from one problem to another :p

hello,

I recently started a setup with a water cooling system. I had some issues, but I ironed them out. Today I started to fill the system with coolant, but almost immediately I got a leak from the Swiftech NB block. Although it almost gave me a heart attack, I got it cleaned up (just the water, I'm assuming there is no residue remaining?). However, in replacing the block, I may have overtightened one of the screws. The result is the screw will no longer properly tighten. It will keep "turning" no matter how much I try to tighten it; it remains loose-ish. The block attaches to a kind of copper heatpipe system (Asus R2E, it covers the MOSFETS, SB and NB). Have I damaged the thread inside the block which the water block mounts on?

I can get it replaced with scansure, but I just wanted to check if there is anything I can do myself to repair it first.