Hi,
I have faced the exact same issue.
I was giving the test in the order - V,Q,IR,AWA.
Verbal went smooth. During the Quant Section, suddenly the screen read an error message - contact admin. I relaunched the exam, fortunately it got loaded, although from the 15th question (which I had already given), I should have got the 17th question. The timer had been going on it seems as instead of 34 Mins, I had 30 Min left.
After the IR section was over, instead of giving me AWA, the software again gave me IR and the entire screen froze with the dialog box- Please Wait. Its been more than 1 hour, but the screen is still frozen.