> Note that based on the error you may have run out of Windows handles. If
> you can monitor named, check the number of handles that it's using. This
> is not shown by default in the task manager, you have to add the column
> handle count in from the View->Select Columns menu. While you are at it
> add the thread count. This will give an idea of whether there is a handle
> problem. Also run netstat -aon and count the number of open sockets by
> named.


Unfortunately Windows netstat don't show the process owner, but looking the
ports there are only a couple open socket by named.

Task manager show for this server (2G of RAM, run 2 days) following numbers:

Mem usage 839 488 K (and rising every cycle)
Handles 3466
Threads 13

Jukka