It could be a bug in IE. Recently, on one of my PC's, all of my plugins got screwed up. I can't open PDF files directly from the browser, and instead get a white screen, a popup box that says "Adobe Acrobat" and an OK button which does nothing. I also use Skype, so it should be converting phone numbers on websites to a format where I can just click on the number and it will dial. I checked to see that the plugins were still enabled and they are. It will likely require that I reset IE to defaults and/or re-install Adobe Acrobat and Skype. So In this case I feel your pain, but can provide no useful anser to your problem.
Make sure the Adobe plugin is not disabled in IE8 would be my first suggestion.