The specific setup has been running fine for years.
Suddenly yesterday, the following error message appeared when attempting to log in to AX:
"Cannot create instance of CLSID_VSSDatabase. Check that Visual SourceSafe client is installed properly."
I tried connecting using the client on a different machine and that worked fine.
Therefore, I realized that the VSS client installation on my machine must be corrupted.
I ran the repair utility and that solved the problem.
Hope this is helpful to any other person that might come across this issue.