This link shows you the settings that need to be checked - https://support.mozilla.com/kb/Opening+PDF+files+within+Firefox

That support article uses Adobe Reader as the example for settings. You have Foxit Reader Plug-In For Firefox and Netscape installed, so you're going to have to look for the preference to have the PDF displayed in the browser window in the FoxIt preferences.

Thanks this helped - don't have adobe but the same pretty well applies to Foxit.

I had this problem. I downloaded Foxit and went to Tools>Options>applications> and changed 4 adobe Acrobat(firefox) entries to point instead to ProgramFiles>Foxit>Foxit.exe The system finally works!

I have had this problem in Firefox version 3. I updated to Firefox 4 and again I received a message that Adobe Acrobat could not be opened witthis browser. Howver, I went to "Opening PDF files in Firefox" in Firefox support. I followed the instructions under "Check Firefox settings". Iset the Action for Adobe Acrobat Document to "Use Adobe Reader 9.4 (default)" and IT WORKED.

I had the same problem, so I went into Tools / Options / Applications and changed from "Use Adobe Acrobat (in Firefox) to "Use Adobe Acrobat 9.2" and it works fine. Hope that helps. Gainsay14

I had the same problem, foxit has a new version of the plugin for Firefox 4. You just have to desintall and reinstall foxit reader, it worked for me.

I would like to tell firefox to download and open PDFs using Adobe instead of a plugin. Is there any way to do this?