FedEx Mod not reading weights

Hi there. I've got an older version of zen running (1.2.7) w/ the FedEx Mod. We're only using it for Express options - everything else is free shipping. Rates are being returned, but they don't seem to be taking weight into account. I'm not sure if this is true with all products, but a tested changing the weight on a couple & got the same rates. Changing the zip code does change rates. I've looked through admin & don't see anything that might cause this.

Any ideas?

Thanks!

make a drastic change in weight,
the fedex module does in fact use the weight, ship from and ship to addresses in its calculations

Yeah, I did that. From 20 to 70 to 5..

I did discover however that it's not a FedEx problem - it's a shopping cart problem. When I have the shopping cart display order weight, it's always 0. The number of items in cart change, but not the weight. Could this have anything to do with our free shipping settings?

Thank for your helpl.