Windows 7: NSIS error help!

I am now back online after a week of messing about with talktalk, BT and my router
least its working some shape,
anyway had trouble before it went down with AMD drivers causing flicker/crossfire problems.
So trying to sort it has brought another annoying problem every single time I try to run an amd installer I get this NSIS ERROR message, I have searched on the net for a fix tried all that I found none which work
Downloaded drivers again but still getting error message.
Anybody know what to do cos I don't.