RTFM problem

I have installed RT 3.0.10 and RTIR 1.0.0. They work nicely.

Now I have tried to settle RTFM 2.0.4, but I have the next problem. When
I want to give rights to a group or users within the RTFM, I get the
next message: “System ErrorRights could not be granted for RT::FM::System”.

Anyone know what I might be missing?