You said you have an "activation problem". Is that because you think the "orange" indicator means there's a problem?
Orange is caused by either:
- you've got a zone restriction applied to the module (see the "Zone" pulldown and set it to --None-- if you don't want a zone restriction applied).
- or you've set the "Enabled Status" (first radio button in the settings) to False.

There's no need for a password in the USPS module.

More important is ... when you go to checkout, do you get shipping quotes?