Hi Davidcrossuk68, how are you?
I am an independent consultant and user like you!
I'm happy to help you!
Does the error occur only in one file? Or in all files with the .AVI format?
Did you test opening this file in other display software?
Check and make any pending Windows updates, this will correct possible codec errors.
This error is happening because Windows is not finding the Codecs to display the file type.
After updates have been made (if any), and the issue is still not resolved, you must download and install audio codecs to resolve the issue.
There are several ways to achieve them. Many sites offer it. So the best for you is to search for 'Download Windows Codecs', and thus download the tool from where you have confidence and preference.
If you still have a problem I hope your answer!
If this was helpful, mark it as an 'Answer'. If more users have the same question, it can help them!
If you still need help, comment here and I'll be back to help!
Best Regards