ndiswrapper will not load

I recently installed ubuntu 7.10 on a dell dimension 4100 , I have never work with a linux ops before this. I want to use a netgear wireless adapter on the system. have tried several time to install ndiswrapper , get same error ( w: failed to fetch: ( ubuntu 7.10- gutsy gibbon -( release i386(20071016)}/pool/main/n/ndiswrapper/ndiswrapper utils-1.9-1.43-lubutu2_i386.ded ) hash sum mismatch. Has anyone had this problem and is there a fix ?