This is a very generic, low level error message, which could be a result of any number of situations, not every crash that generates this error is the same.
If you think the problem is caused by an agent, there are a few things you can do to assist diagnosing the problem. To identify the problem you should turn on agent manager debugging (see this for details, if you not familiar with how to do this:http://www.notes.net/today.nsf/9148b29c86ffdcd385256658007aaa0f/27f79cb66e381900852565b6006d2eb4?OpenDocument
When the crash occurs you will be able to see what agent in what database caused it. If you could submit both the database (indentifying which agent caused the crash) and the rip file to Lotus Support you will give them enough ammunition to figure out what happened. There is something specific in your agent/environment that causes this scenario, it is not possible to diagnose it in the forum.
Julie _ Iris