On two occasions today the cluster node running one of our NDPS managers has ground to a halt and become unresponsive reporting 100% CPU utilisation.
Had to force a restart of the server to allow the print manager and broker to load on another node.
Looking through the ndpsmmon.log, there are numerous entries such as:

5-07-10 12:21:50 pm, Operation: List Object Attributes,
Service Error: Database Object is In Use [1000008, -914, 0],  
User Name: [USER NAME],  
Address: [IP ADDRESS],  
(Client Interface)

5-07-10 12:25:36 pm, Error: Database Object is In Use (-914)
Printer Agent: [PRINTER NAME] (Operation code: 106)
(Gateway Interface)

5-07-10 12:26:19 pm, An operation used 304 seconds.
Printer Agent [PRINTER NAME] (Operation code: 106)
(Gateway Interface)

Having loaded the print resources on another node, they worked as normal for a couple of hours and then a similar sequence of events returned.
The print manager is running at the moment, but I'm not sure how long that'll last.
Any ideas as to what might be going on here?
We're running NW6.5 SP8, iprint components from the "8c" update set and mostly XP clients on a range of iPrint client versions (5.32 - 5.40).

Thanks in advance,