Limit the number of master terminals you have defined. By that I mean in environment variables and in ibercfg.bat make most of them master and server capable false. You only maybe want 10% of them to be master and server capable in that large of an environment. That will cut down on network traffic and help with performance. Also check your debouts, there is one for rfs on every terminal, see if you can see any fatal errors in there around the time the translog corrupts. And remember, not every version is perfect, you may find another is better. I hear the latest 6.2, 6.2.21 has the best rfs files yet.