Ah, ok, so TCA ist just TClonesArray ...
For some strange reason, I had used PndSttFind/FitTracks instead of PndLheTrackFinder/Fitter ... bad mistake, especially, since the original version of the macro contained the now obsolete PndTpcLheTrackFinder/Fitter.
Still, now I get another error in the Kalman task:
Error in <PndLheKalmanTask::PndLheKalmanTask::Init>: PndTpcCluster array not found
-E- FairRootManager Branch: GEMHit not found in Tree
Why Tpc? There is no Tpc in our simulation ... and what about GEMHit?