Wait are you running dual external monitors?
DVI monitor and display port monitor? I thought that was only possible on desktops, mini,imac, MP?
out of the box the macbooks only do one external monitor with the minidisplay port.
you can add additional display outputs using USB
I purchased this newly released model from here: http://sewelldirect.com/Sewell-Minideck-USB-to-DVI-Display-Adapter.asp
display link adapters have been around for a while but my monitors run at 2048 by 1152 and this was the first usb adapter that promised that resolution.
If you dont need the high resolution support (2048x1152) there are many other solutions out there for usb display outputs.