cannot start 2 "Not yet started" sub-activities

We are at  a TDTIM "start data transfer" .

2 final sub-activities

RSBERRORLOG

X_CSZDORECNO

are in the queue called "Not yet started".

We have tried to start them several times, including the use of "automatic repair".  However they are

still in "Not yet started".

Would you please share your experience on this. i.e. how to start them?

Thanks!