Whenever I download anything from any site, Mozilla appends the downloaded file name with ".pdf" and attempts to launch Acrobat Reader Plugin, which then gives an error with those files that are NOT truly .pdf files. This happens even after I turned off the Download Manager under the Downloads tab under Navigator in the Preferences window. I have to go in manually to the downloads folder, which is the default C:\WINDOWS\TEMP folder on my machine. I am running Build ID: 2002110508 on a AMD Duron 900MHz system, with 512 MB SDRAM, on a Windows ME OS. It is not critical, because I can go to the downloaded file, remove the .pdf extension that Mozilla added during the download, and all works fine.
Check your helper app settings -- sounds like you associated the application/octet-stream type with the .pdf extension....
Not a bug. I had somehow associated the application/octet-stream type with the .pdf extension in my Helper Applications folder under Preferences. Removed the association and now have no problems. Thanks to Boris! :-)
Marking WFM in the 2003-01-03-08 trunk under Windows XP.