First I have to say I prefer the virustotal scanner as a) it has currently 37 different scanners and b) it uses the windows version of avast, so it more in keeping with what you have.
The main thing is that the important version of rundll32.exe in system32 is OK. Well lets put it this way it is the same as mine and a) I don't get any detection by avast and b) I have no apparent dll issues which would be apparent if it were infected or corrupt.
The versions in the other locations are likely to be different but for S&D to get detections on all I find highly suspect. But then again there are the jotti results
Personally I would probably discount the S&D results and go with a) not experiencing any rundll32.exe problems, e.g. other dlls not running properly, b) suspicious behaviour, pop-up ads, redirects or attempts to open web sites you didn't request, etc.
So I have decided to upload my version of rundll32.exe to virustotal and there are zero hits from 38 different scanners,
http://www.virustotal.com/analisis/1bd0ad1185cf0ffb35facbf1ec6a43e5. Since the MD5 of your file is the same you can assume yours too is clean.