SetUp Files Corrupted...

I'd really appreciate help on a problem which, after much time and effort still defies solution. I have used SPYBOTS&D for over a year without difficulty. When their site informed me a new version available I downloaded. (Probably here as well as at several other sources).

At Install the message above appeared immediately. Said to try installing again. Did so; no change. Went to the URL support who, among other things, had me download program directly at their site. No change. Then they had me send HJT log and after examination, had me FIX three files: 09 Extra Button; 09 Extra Tools menuitem: Show & Related Links; 016 DPF. Thereafter tried Install from desktop icon remaining from last download. No change. Deleted and downloaded again, NO CHANGE.

Now advised A2Squared also has an update. Downloaded from here (as well as at another source). Same result. Maybe the glitch is catching! Never experienced anything like this, and no problems with any other computer use. This is Win98SE., IEv6, 192 Ram (much trouble with low System Resources, but that's another chapter).

Will welcome assistance which will uncorrupt those SetUp Files.

Cordially,