Sorry, I guess I didn't provide much info, did I? I am using Monarch to access Paradox tables (.DB). I am using the Monarch Open Database, Browse, Local or Network File ... option. I have been successful many times in the past including these exact tables. The native program that creates and updates these tables continues to work fine. I used another person's work stations and Monarch, and it works! So some setting that is used by Monarch to open Paradox tables has changed on my workstation. (Using the same steps I can open other data types like Excel and Access). I don't know enough about it. It's always just worked.
Monarch 10.5 on Windows 7.
Hope this helps.
A little hunting on the error number suggests it's not a registry issue but a permissions issue - if you have local admin rights it should work.
It might be that your IT environment has got an updated security policy that has silently affected your rights.
I think it's perhaps something that your IT department, together Datawatch's support team, can help find a fix for.