message: protection +error message
diff: @@ -303,6 +303,10 @@ AliESDtrack* AliPIDtools::GetCurrentTrack() {
  }
  lastEntry=entry;
  }
  + if (branch==NULL){
  + ::Error("AliPIDtools::GetCurrentTrack","Branch does not exist, entry %d",entry);
  + return 0;
  + }
  pptrack = (AliESDtrack **) (branch->GetAddress());
  }
  return *pptrack;
  @@ -320,6 +324,10 @@ AliESDtrack* AliPIDtools::GetCurrentTrackV0(Int_t index) {
  branch1 = fFilteredTreeV0->GetTree()->GetBranch("track1.");
  treeNumber = fFilteredTreeV0->GetTreeNumber();
  }
  + if (branch0==NULL || branch1==NULL){
  + ::Error("AliPIDtools::GetCurrentTrackV0","Branch does not exist, entry %d",entry);
  + return 0;
  + }
  pptrack = (index == 0) ? (AliESDtrack **) (branch0->GetAddress()) : (AliESDtrack **) (branch1->GetAddress());
  return *pptrack;
  }
  