I upgraded from Acrobat 6 to Acrobat 8 and immediately begain getting the "distmon" error every time I started Excel. I tried every single suggestion in this posting and every other relevant website with no success. Some of them I tried twice. The only fix was:
1) uninstall Acrobat 8 (required reboot)
2) reinstall Acrobat 6.
3) uninstall Acrobat 6 (required reboot). After reboot the "distmon" error in Excel was gone.
4) reinstall Acrobat 8 (required reboot)
In my case, I looked everywhere for pdfmaker files - nada. Turns out my AppData folder was redirected in Group Policy to a folder on the file server. I then looked in the redirected folder on the server " \AppData\Microsoft\Excel\XLStart\ " and there it was, pdfmaker.xla... nasty filthy little maggot.
I deleted it - problem solved.