If their is something stuck you should be able to find it in the queue directory for that queue.  I think it is like u\data or something like that.

We had the same issue with 9971's. The resolution for us was under locations.  We only had allocated video bandwidth of 384 kbps per location and that was fine for one call but as soon as the second went across the WAN/DP then we would get dead air s...