Task scheduler error code - (40,4):LogonType:

I have an application that schedules tasks.  99% of the time it works fine, but some users get an error atRegisterTaskDefinition.

I am doing TASK_CREATE_OR_UPDATE with Task Logon Type set to TASK_LOGON_PASSWORD.

The exception is: (40,4):LogonType:

I cannot find these exceptions documented anywhere, we can't fix the problem without knowing what this error means.  Can anyone point me to the documentation?  I think the 4 means "batch", but I'm clueless about what "40" represents.