Acroread Firefox plugin Ubuntu 12.04 issues

Question

Since I upgraded to Ubuntu 12.04, every time I try to open a PDF through Firefox (which I like to do quite often as I read a lot of PDF documents and downloading each then deleting is tiresome) I get the error message:

Could not launch Adobe Reader 9.5.1. Please make sure it exists in PATH variable in the environment. If the problem persists, please reinstall the application.

If I launch Firefox from the terminal the message it gives when attempting to open a PDF is:

(firefox:5989): Gtk-CRITICAL **: IA__gtk_widget_realize: assertion `GTK_WIDGET_ANCHORED (widget) || GTK_IS_INVISIBLE (widget)' failed

(firefox:5989): Gdk-CRITICAL **: IA__gdk_window_set_back_pixmap: assertion `GDK_IS_WINDOW (window)' failed
/usr/bin/acroread: 23: exec: /opt/Adobe/Reader9/Reader/intellinux/bin/acroread: Permission denied

How can I fix this?

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I should mention loading a PDF from say the Desktop is fine. I only get error when loading a PDF via the browser.

ADDITIONAL INFO:

ldd /opt/Adobe/Reader9/Reader/intellinux/bin/acroread | grep not 

libBIB.so => not found
libBIBUtils.so => not found
libACE.so => not found
libAGM.so => not found
libCoolType.so => not found
libAXE8SharedExpat.so => not found
libJP2K.so => not found
libAdobeXMP.so => not found
libicuuc.so.36 => not found
libResAccess.so => not found

Answer 1

The problem is obviously caused by apparmor.

All you need is add a line to /etc/apparmor.d/usr.bin.firefox and reload the rules.

e.g inside the brackets,

  # Allow execution of adobe reader
  /opt/Adobe/Reader9/Reader/intellinux/bin/acroread ixr,

I don't have a 32bit machine, those were not tested.

Answer 2

I would first try fixing permissions, since this looks like a lack of exec-permissions:

sudo chmod 755 /opt/Adobe/Reader9/Reader/intellinux/bin/acroread

This resets the file's permissions to be read and executed by world and group, and read, written, and executed by owner. Now, we'll set the owner to root, for good measure:

sudo chown root: /opt/Adobe/Reader9/Reader/intellinux/bin/acroread

and try again.