When I first got my RapidFire for my A4000 there was times it played dead or was reported faulty by the system. I traced the problem down to the card not seating properly in the Zorro slot and therefore not making proper contact. As my A4000 is rehoused in a PC tower the cards are now vertical and what I did to fix the problem was to use a Lego block stuck to the floor of the case to hold the card in place. Now the card works fine every time.
Hope this helps you.
