Unable to Uninstall SEP

Hi There,

I am unable to uninstall SEP on some Windows machines (server 2008 R2 and Windows 7).

When I attempt to uninstall from Programs and Features I get the below error message.

Now the Sep64.msi does actaully exist in the location where the uninstaller thinks it is but I think the problem is that the version installed on the computer is 12.1.1000.157 and version on the network share is 12.1.1101.401.

I can't find the media for the older version so how do I uninstall it?