PlayOnline missing graphics+flashing textFollow

I've recently bought FFXI for my PC, and am a newbie when it comes to MMORPGs. When I installed PlayOnline, I immedietly ran into a problem though: text flashes, disappears and reappears, and bars are missing, with only the four corners and the text visible. I tried uninstalling it and reinstalling it again, but I still have the same problem...

How am I suppose to play FFXI when my PlayOnline makes it impossible for me to see what the heck I'm doing? Is something wrong with my computer (Windows XP) or is it the program itself? What a disappointment. :(