I found several threads listing the problem of a dll not being a valid image. In almost all of the cases, it was suggested spyware, malware or trojans are the cause. Aside from updating virus and spyware software and running it (preferably in safe mode) it was suggested to run a Hijack This log and analyze it carefully.
If you dont have HJT you can download it
here, then close your browser and run it. If you are unfamiliar with how to read the results, you can PM me with the results *copied and pasted*
(please do not attach a file as I won't open them) into the PM. It might take 2 or even 3 PM's to copy and past the entire thing in.
Please let me know if you need assistance with this, or what results you find.
I might mention, while it's best to only have one virus scanner on your machine and running at any given time, I personally find that no one single solution does it all for spyware and malware. I'd strongly suggest either trying some of the free versions (you can always remove them later) and/or doing some of the online scans for malware. I personally have 3-4 soyware/malware programs I run on a weekly basis (tho I don't run them at the same time, nor do I leave them running all the time) and each one tends to find different things.