Recently, I noticed that on all (three) of our ZENworks Primary Servers I was unable to run any zac content distribution commands (zac cdp, cds, cdi, cvc, etc). All attempts return the following:

Error processing the ZAC command. Could not find a command matching request

The zmd-messages.log file (zac logger level is DEBUG) then displays lines showing:

[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [***************** Exception Dump ***********************] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [Exception processing the command] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [------------------------------------------------------------------------------------] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [Exception Type: class java.lang.NullPointerException] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [Stack: com.novell.zenworks.agent.core.zmd.zacserver.ZacAc tivator.getCommandLineHandler( )] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [------------------------------------------------------------------------------------] [] []
[Debug] [06/18/2013 13:37:09.936] [] [4967] [ZenworksAgent] [3,396] [CommandLineManager] [***************** End Exception Dump ***********************] [] []

I was curious if anyone had perhaps encountered this, or has advice on troubleshooting procedures for such an error? This is affecting all three primaries, and no ZCM or OS updates have been applied since the last time I remember using these commands successfully (which would have been a few months ago). Time is in sync, DNS is functioning properly, the certificates are valid, and the external MS SQL database appears to be running fine. The zone as a whole seems to otherwise be functioning normally, although this issue was discovered when a bundle got stuck in the "Packaging" phase and we went to troubleshoot what was going on. Since then however that problematic bundle was deleted and other (content-holding) bundles have been made and synchronized normally (to all primaries and our 33 satellites).

Our zone is currently 11.2.1 MU1, and while I was planning to update it to current levels in the next few weeks I now would prefer to verify there isn't a pre-existing problem going in. If anyone has experience with this or similar-sounding issues, any advice/suggestions would be very welcome and appreciated!