In order to process a cube, you must first process the dimensions. I start with the rule of processing shared dimensions first, non-shared dimensions second and the fact table last.

In order to isolate your problem I suggest processing in this sequence manually. You may get lucky and find the dimension that is causing the hanging.

If you manage the whole process manually, then this points to the order that your job is processing them in. Monitor the job and make sure the ordering is correct.

as a side issue, ensure that you have enough disk space to be able to handle the transaction logs. I have seen these fill up like crazy in the past on some systems I have taken over - Never my own creations, of course.