Error message at startup 'Stub has stopped working'

I'm operating Vista 32 bit and have done so for some time without problem but as of today I've started to obtain an error message stating 'Stub has stopped working' which prevents the startup continuing until I cancel the message.

Can anyone help me to understand:

What is this?
What has caused the error message?
How can I repair the error/problem

Hello RsC and welcome to the forums

Can you do the following for me please?

OTL

Download OTL to your desktop.
Double click on the icon to run it. Make sure all other windows are closed to let it run uninterrupted.
When the window appears, underneath Output at the top change it to Minimal Output.
Under the Standard Registry box change it to All.
Check the boxes beside LOP Check and Purity Check.
Click the Run Scan button. Do not change any settings unless otherwise told to do so. The scan wont take long.
When the scan completes, it will open two notepad windows. OTL.Txt and Extras.Txt. These are saved in the same location as OTL.
Please copy (Edit->Select All, Edit->Copy) the contents of these files, one at a time, and post it with your next reply.

CKScanner

Please download CKScanner from here to your Desktop.

Make sure that CKScanner.exe is on the your Desktop before running the application!

Double-click on CKScanner.exe and click Search For Files.
After a very short time, when the cursor hourglass disappears, click Save List To File.
A message box will verify the file saved
CKFiles.txt will be created on your desktop, copy and paste the contents of this into your next post

Malwarebytes Anti-Malware

Download and install MBAM from here
Run a full scan and copy and paste the contents of the log into your next post for me to analyse

Tom

Also try a system restore, one week before the problem began