A new Product Activation Key (PAK) is required when upgrading from LMS 4.0.1 to 4.1. The PAK is then used to obtain a license file which will be necessary to operate version 4.1 at other than the evaluation version restrictions.
Cisco customer support should be able to ascertain your LMS 4.0.1 contract coverage (assuming it's been purchased) even if you can't find it yourself. Seeing as how LMS 4 just came out last fall, it can't be too deeply buried.
For future reference, you should associate your cisco.com userid with your service contract number(s).
Hope this helps.