Updated and now can not open Avast Pro

I have just updated Avast Pro and now when I try to open from my desktop in order to run a virus check I just get the message “Failed to load language dll [1033\UILangRes.dll]” I have no idea what this means or how to fix it. Any help will be much appreciated.
Duncx

A full reinstall may cure this

Download Avast Uninstall Utility to your Desktop.
Download the correct version of Avast
Avast Free
Avast Pro
Avast Internet Security
Avast Premier
Disconnect from the net
Uninstall Avast via control panel

[]Run the uninstall tool and accept the reboot to safe mode
[
]Once complete reboot your system
[*]Reinstall Avast


Before a complete uninstall and re-install you could first try to repair Avast:

Start > Control Panel > Programs & Features > Uninstall a Program > select Avast and click " Uninstall/Change ". Choose " Repair " and “Continue”.

Once the repair is completed make sure you reboot your computer for the repair to take effect.

Upgrading from Free version to one of the paid version is throwing this bug.

Repair Avast:

Start > Control Panel > Programs > Programs & Features > uninstall a program > select avast! and click " Uninstall/Change ". Highlight " Repair " then Continue. Reboot when finished.

If it does not work, reinstall Avast. first run avastclear.exe then download Avast from one of these links and reinstall:

Online installers
http://files.avast.com/iavs9x/avast_pro_antivirus_setup_online.exe

Full installers
http://files.avast.com/iavs9x/avast_pro_antivirus_setup.exe

Remenber to reboot when it is done.