Steps to reproduce this bug which disables the ability to create new list: 1. Search for patrons in staff side. 2. Select one or more patrons from the list. 3. Next to the text "Add selected patrons to:" choose [ New list ]. 4. Give that list a name. 5. Click save and notice the alert "an error occurred".
Seems like the error was only with the kohaadmin account. This bug can be closed.