Problems with file downloads and roles on ubercart 3

Hi - I'm fairly new to drupal so I suspect there's probably something very simple I haven't got right here. I set-up drupal 7 with ubercart 3 on my local pc last week and also enabled the various bits and pieces I needed for both file downloads and role assignment in ubercart. This worked fine and I was very impressed.

I've now installed the same configuration (as far as I can tell) on a live server but am having problems with both file downloads and role assignments. The main store page is telling me that I've got everything set-up properly ie

File downloads - The file downloads directory has been set and is working.
Roles - The role(s) member are set to be used with the Role Assignment product feature.

But, in the Products section of the Store page, there is no link for View File Downloads and if I edit a product there is no tab option for editing features (and therefore I can't do role assignments).

I'm using a standard theme - Bartik 7.19 - and as I said, the same configuration seemed to be working fine on the local pc.

Anybody any idea what I might be doing wrong?

cheers,
Gordon