Hi Cathy,
Unfortunately I cannot answer your question, but I am just wondering how this has happened. In 2003, he has been dependant of a work permit holder, therefore he had been elligible to work WITHOUT any other work permit. How his company have applied for a work permit, I wonder, since he has not been requiring it.
Probably you should raise this issue with the HO saying that the work permit in 2004 has been mistakenly issued, then they may invalidate/ignore it and he can be considered as your dependant again.
P