Normally, that would indicate they're doing something right. In a region where state controlled news media are the norm, a truly independent press can be seen as a threat to the status quo.

On the other hand, the US has some concern that the bin Laden tapes might be containing coded messages to terrorist cells around the world. The BBC used that trick a great deal to communicate to resistance groups in occupied Europe in WWII. With most other forms of communication cut off in Afghanistan, issuing a press release would be an effective means of communication to outside groups. Bin Laden is no fool. The possibility has to be taken seriously.