Guest Additions not working after install

Hi I am running a Windows 7 host, with ubuntu guest. I have mounted the guest additions .iso onto the ubuntu guest and ran

which worked fine, and was then under the impression that by restarting the virtual machine Guest Additions automatically kicks in. This is not the case and I am without the use of a mouse within the guest, with only keyboard access working.

Anyone have any suggestions? Is there something else I am required to do after running ./VBoxLinuxAdditions.run?

Thanks very much.