The messages are telling you that the drup_uc_shipments, drup_uc_packages and drup_uc_packaged_products tables don't exist in your mysql database. Was there a problem with a page hang or something when you enabled the module?

Did you enable some ubercart modules and test it before enabling the shipments module?

If you have shut off shipments you should uninstall it too. In the /admin/build/modules page use the uninstall tab and put a tick in the shipments module checkbox on that page. Then if you re-install it it should at least create those tables in the mysql database.

There might be an issue with the orders that exist not having shipping information, but getting the tables created is probably the first priority.