SD Card troubles

[Escaep]

I recently bought a 4 GB PNY Optima SD HC card for my camera. However, I can't get it to work when i want to transfer pics. It works perfectly in my camera, takes pictures and all so i know it works. What happens is that when i plug it into my card reader then into my computer (I'll add on this later) ((in xp)) about four separate drives show up--but all of them are empty. A couple of weeks ago I was at a beach retreat for my church and tried to copy pictures over to my dad's laptop that had XP on it and the before said problem happened. I took it to one of my friends who had an XP desktop and it did the same problem. The weird part is that I took it to another friend who had a Vista laptop and it worked flawlessly. I have also tried it on my iMac with OSX Leopard and it says the disk is not readable by this computer.

So i am here to ask what the problem is. Why would it not work on XP and OSX but work on Vista? I have went to PNY's website but found nothing such as updates or drivers or anything. Can anyone help?

--Escape

 

[Eejit]

Drivers for the adapter?

 

[CyberPitz]

Have you tried getting your hand on a USB card reader just to get things moving along for now, and then worry about the driver issue for the card reader later?