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I'm asking my question here because I can't find an answer anywhere else and the Ubuntu forums have not helped at all.

I am running Firefox and Ubuntu 11.04 on a Dell Dimension 9200. Everything was working fine up to the point where I opened a file in Firefox...

I downloaded several file using Firefox 4.01. While downloading the files Firefox opened the small Downloads browser window as is normal. I then right-clicked on a PDF file and chose Open with Okular. The file did not open. I did a right-click on the same file and chose Open Containing Folder. This failed as well.

The problem I now have is every time I try to open anything from the Firefox Downloads browser window it tries to open it with Okular. I also cannot right-click the file and use Open Containing Folder because it also tries to open in Okular. Everything now tries to open in Okular. What is stranger still is that now if I try to open any of my folders fro the Ubuntu Places menu (such as Home Folder, Videos, Pictures, etc.) they all try to open in Okular. None of them actually open and all I get is the following error message:

Failed to execute default file manager. Failed to execute child process " /user/bin/okular"

I have uninstalled and reinstalled both Okular and Firefox. I even deleted all of the Firefox preference files and I still get this error message.

I am also wondering if it may be that my Kensington Exper Mouse trackball driver/software has associated all of these actions with the right-click on the mouse (that is, everything that happens with the right-click tries to open in Okular).

Any suggestions on how to correct this problem?

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Looks like your mimetypes are messed up. Have a look at my answer here: Chromium "Show in Folder" opens in text editor If this is not what is wrong with your setup please leave a comment!

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