Many modules use core service APIs. The problem you are seeing is the result of a breaking change introduced somewhere around the 3.03/4.03 releases of the core DNN product. I believe the API call for getting UserInfo changed at that time. 

So, if you are running a version of DNN that is pre-3.03/4.03, and then install a module that was compiled against a newer version of the core, you will get that error. For example, running the latest version of the Repository module (3.01.15) against an older version of DNN (3.01.13) you WILL get this error a lot. Conversely, if you are running an older version of module against a new version of DNN, for example, running Repository 3.01.13 against a 4.05 DNN core, you will also get this error.

As I said, this is not restricted to just the Repository module.

Check your DNN core version, then on the Module Definitions page check the versions of the modules you have installed and make sure they 'match' up.  You can see what the minimum required DNN versions are for each module on the Download page.