I have attached a screenshot as requested for the main error that appears first.

I do get a second message saying ‘Avast unable to connect to Avast engine. Avast mail protection cannot be started’

Followed by a third error message saying 'The add-in “C:\Program Files\Alwil Software\Avast4\ashOutXt.dll” could not be installed or loaded. This problem may be resolved by using Detect and Repair on the Help menu. Unable to load “C:\Program Files\Alwil Software\Avast4\a…”. You may be out of memory, out of system resources, or missing a .dll file.

I have also checked the ‘aswCmnB.dll’ file and it says that it is version number 4.1.304.0? - Although I have downloaded the latest version and this is confirmed if I try and download again?