Hello.
Please note Free license is limited is some features, like number of users, editors, products, documents, and so on. So it seems you got over some license limit, when you imported given object, maybe number of blogs, or something like that. You should see more details in Event log, in Site Manager -> Administration section.
You can also see full feature matrix here (where you can see limitations for all license editions):
http://www.kentico.com/Downloads/KenticoCMS_55_R2_Pricing_for_Web.pdf Best Regards,
Radek Macalik