Error Installing Multicharts.net from TWS

I have just upgraded to the latest version of TWS (9472) and tried to install the integrated Multicharts.net. First attempt didn't work at all so I restarted my PC (Windows 7 SP1) but now get the attached error. If I click retry, the error remains and if I click either cancel or ignore, the installation starts again but stalls at the same point. Any help here would be appreciated

Hello sean007,

Please try disabling the anti-virus on your PC.
Do you have Administrator rights for your Windows Account? If you don't have them - please try logging in as Administrator and running the installation again.