export audio mixdown

cubase 6 64 bit and export audio mixdown .I have 2 tc powercore cards 64bit and a uad 64 bit card in a brand new creation station. I can not do an audio mixdown if any of these plug ins are on. It works fine without the plug ins. I get this error message:
a cpu overload occured during the export

I I would just like to say that I’ve had same problem and I solve it updating my plug in information (devices Tab)
good luck