I'm just guessing like everyone else. But if in fact DT has resigned, or there needs to be a restatement of previously reported results, that will presumably effect the timing of the 10-K filing. Under the circumstances (that being the absolute pounding the stock would take if this was announced) it may be that CCME has asked for the halt in order to work on the restatement (hypothetically of course) or to make arrangements with another auditor to take over for DT, then request a filing delay from the NAZ.
Again this is clearly all speculation, I'm not trying to be a downer.