Do you backup your AIX server to a Windows Server with Symantec (former Veritas) Backup Exec? In this case you should own a license that entitles you to support and I'd ask Symantec to solve your problem.

However, as an AIX admin who's customer is tight I'd simply use the Workload Manager to set that agent to a fixed CPU limit. Find out how much CPU the application needs and give only the rest to the agent. WLM comes with AIX since 4.3.3 at no further cost.