Recently I updated my physX drivers, which lead to constant UT3 crashes.
I'd like to reinstall UT3, but when I try (using Add/Remove Programs, or the "uninstall" button when you insert the UT3 disk) I get the following error:

1154: Installer not found inC:\Documents and Settings\NAME\Application Data\installShield

How do I go about uninstalling UT3 without this?
If it's not possible, where could I get this file?