By setting selinux to "permissive", you've, in effect, turned it off.
SElinux will still provide messages about infractions, but won't prevent things from running... i.e., it is no longer guarding your system.
hth, ken
Thanks for the reply; the fact that the error only occurs when Enforcing is basically the point I am trying to make...
The absence of AVC messages is what I found troubling. In the past, every SELinux denial I've seen has been logged. I will increase the loglevel and try to get more info.