Difficulty opening pdf docs in Firefox

[Peter Kinross]

Every time I open a web linked pdf in Firefox I get a couple of dialogs. I have to close one before the pdf doc will come up.
The one that I have to close, has a heading saying 'Adobe Acrobat', and a message saying 'Cannot use Adobe Reader to view PDF in your web browser. Reader will now exit. Please exit your browser and try again.' But when I close this dialog the pdf doc opens.
The second dialog has a heading 'Pagemarks'. It has no message in it's blank message area, but contains 4 buttons 'Open'; 'New' (grayed out); 'Delete' and 'Close. However the pdf doc opens even with this dialog still open.
I have Adobe Acrobat 8.2.2 and Adobe Reader 9.3.2

[HansV]

I'd dump the bloated Adobe Reader and replace it with the free version of Foxit Reader. It's smaller and faster, and its Firefox plug-in works well for me.