Well, I guess FileWriter not working on Linux is a actual UT3 bug, not my bug (for a change).
I've exchanged a couple emails with Ryan regarding FileWriter. He said he would look into it. I guess we all just need to plead with him to fix it with the next patch.
My mutator is working well dumping DM and TDM events. I think there is still a bug or two regarding players changing teams. The output files mimic the old UT logs but the schema and interface is quite different. I run 1 server with 5 to 10 friends at the most, so our stats are geared for a very-semi-organized very-small community. I'd be happy to pass along my mess, uh, I mean code