Good luck,may as well add the MBAM updayes in case you are blocked.
Manually Downloading Updates:
Manually download them from HERE
and just double-click on mbam-rules.exe
to install. Alternatively, you can update through MBAM's interface from a clean computer, copy the definitions (rules.ref) located in C:\Documents and Settings\All Users\Application Data\Malwarebytes\Malwarebytes' Anti-Malware from that system to a usb stick or CD and then copy it to the infected machine.