Downloading PDF files opens iTunes

New to Mac-forums and relatively new to using Macs.
I have a MacBook Pro with OS 10.6.5 and iTunes 10.1.1. My problem, which started recently, is that when I download a PDF file from the internet, the file opens iTunes even though the PDF files are set by default to open with Adobe reader. If I go to Finder and click on any PDF document, they open in Adobe reader. I can't find what I have done to cause this. Any help appreciated.

Welcome to Mac-Forums wvbaldy
Right click a .pdf file, click open with, click "other", click on adobe reader the click the check box named always open with, click ok.

Hope this helps

- Simon

Thanks Simon
I made sure that the "other" was clicked when associating the PDF files with Adobe. As I said before, any PDF file I click on in Finder will open in Adobe Reader. It is only when I download PDF files that they open in iTunes!

What browser are you using? Are you using Firefox by any chance?

- Simon

Simon
Yes, using Firefox 3.6.13.
Thanks for your help.