Mouse not appearing in Ubuntu 12.04

I just upgraded my Ubuntu VM, running under Parallels in OS X 10.7, from 11.10 to 12.04. Unfortunately, at boot, it says, "error mounting /media/psf". I turned to a forum for answers; turns out you have to skip the mount, then reinstall Parallels tools.
Unfortunately, I can't access the virtual disk, mounted in Ubuntu, as Ubuntu no longer recognizes my mouse, or my trackpad. As in, the cursor doesn't even show up. The keyboard seems to work fine, though.
Any advice?

 

Use only the keyboard to install Parallel Tools

You can install Parallel Tools via the command line using only the keyboard.

1. Power up your 12.04 VM
2. Select "Update Parallel Tools" from the "Virtual Machine" menu in the menubar. It might give you a warning about the CD drive still being connected. If you do, just continue on.
3. Click on the VM window to have you mouse captured
4. hit the Command key on your keyboard to bring up the Unity Dashboard
5. type "Terminal" and press return. This should open up the Terminal application.
6. enter the command

cd /media/Parallels\ Tools/

then press return

7. enter the command:

sudo ./install"

8. Follow the instructions in the Parallels Tools installer using the arrow keys and the return key. Once you've finished, it will ask you to reboot.
9. Reboot and enjoy the use of your mouse again.

 

Thanks! That worked perfectly.