Hi Krp,
We've seen this problem before. Basically, something funky happened during the QB install which is not allowing Method to talk to QuickBooks correctly. Check out this link from the QuickBooks Support website. Try the first and second solutions to see if they work, if not then you'll need to go through solution 3 (completely uninstall, then reinstall QuickBooks).
*Note: You'll probably need to uninstall and re-install Method as well.
If none of that works, let us know and we can debug further.
Hope this helps, and happy new year!
Naeem