The main issue with this is that the agent is in such a state that it usually can not run task or policies in a reliable fashion. The resultion involves using methods that do not use the Symantec Management Agent line of communication
After scheduling a task the console will shortly fail the task with unable to get task version object OS error 2147549183 at line 637.
The OS error and/or line may vary.
Corrupted agent store
A script needs to be ran on the clients to stop the agent then delete the c:\programdata\symantec\symantec agent\ldb folder then start the agent.
This usually needs to be done via domain policy or other software like Deployment Server 6.x.
An alternative to running a script on each machine would be to parse a .txt file and use psexec to stop the agent and remove the folder then start the agent again.