You have applied an IPS policy to a Linux agent and you can't override that IPS policy, apply a new IPS policy, or even switch to the built in Policy.
This is an issue if you have tuned the policy incorrectly and not allowed a trusted user, or allowed a user to use the agent tools. Especially if you block the agent from being able to write to the agent.ini files.
I have attached a word Doc with the solution in it please open the attached doc to receive the solution to this issue.