Thanks for all the replies.
The airline only had one set of charts on board, so neither pilot had the ability to refer to the approach chart immediately - but passed it back and forth. The accident happened as the crew misread the crossing height - in other words they descended to the step height the wrong side of the DME fix. With only one chart in the cockpit there was no possibilty of an immediate cross check between the crew.
I wan't aware of this. A bit worrying, especially when flying a complex vor/dme approach with high ground.
Does anyone know if the GPWS sounded and the crew initiate a pull up go-around?