Thanks a lot for your response. That is what I thought too but all weight information is in the DB.
I found that the reason for the problem was that I did not changed the URL in the WA_eCart_FedEx_PHP.php file to point to the FedEx Live Production server (around line 251)
Everthing worked as long as I had my testing credentials but did not work as soon as I changed them to our production credentials which strangely created the No Packages to ship error.
However, after changing the URL to point to the production server to $FedEx_Server = "https://ws.fedex.com:443/web-services/rate"; , everything works great.
Just wanted to share in case someone else would run into the same trouble.
Thanks again and best regards,