Thanks a lot for your reply Sorry for the late reply, System access is already given to the macros.
I have searched a lot and got some information
The problem is something regarding a .dll file not being registered with the system registry.
When this issue is looked into, I have successfully registered the .dll file and now the error am getting is different. It says "Provider cannot be found. It may not be properly installed. "
It is a clear message that DB provider is not properly installed. But I can reload the QV file connecting to the same DB and in this case the connection to the DB is working fine and now I really couldn't figure out what the problem is