You are right, I just wanted to try something very quick so I used the pyWorkPage reference. Tell me how are you running your report exactly? Are you launching the report from the report browser in the end user portal? I had a repeat grid in my work object that was using RD as the source.
getLocalizedTextForString() is engine api and you will not have access to it, it is not a function rule that you can open up in PRPC.