DataSource "0HR_PA_HAP_3" delivers no records

Hi experts,

I am trying to get data from data source "0HR_PA_HAP_3" but unfortunately fail with no records. I've debugged the data source using "RSA3" and found out, that error message "HRHAP00_DOCUMENT 277" ("Template &1 is not assigned to the given Add-On application") internally occurs.

A few notes are the result of my SCN and Internet search, but they didn't help me. Furthermore I tried to find something in the customizing but didn't succeed. Anyone here, who can tell me more about the background of "HRHAP00_DOCUMENT 277"?