Timeout error when exporting audio mixdown in real time

Hi there

In my last works with Nuendo 5.1.1 it occured this problem when I try to exporting audio mixdown in real time. The audio mixdown stop and a message appears: “Timeout error when exporting audio mixdown in real time”. I try to close Nuendo and open it again, but the problem remain. Also restarting Windows the problem remain, and from few days also in older project. I tryed to freeze VSTinstruments and flattening variaudio, but nothing.

I don’t know why this problem occured. Exporting not in real time is right, but working on many project the audio playback sometimes goes in a kind of short loop for few seconds, the bar stopped, then after few second the audio playback return right and the bar re.started after few seconds the audioplayback restart correctly again. Maybe the two problems are connected?

I use Nuendo 5.1.1 64 bit with windows 7, UAD plugins (but the audioplayback problem occurred also without UAD plug-ins), and often i use Rewire VST plug-in for Reason 4.0, but the timeout error occurred also if i freeze this plug in. The audio card is RME Fireface 800.

Anybody knows how to resolve this issue?