Hello jrb23,
This sounds likes something that has happened to me a couple of times when a programmer has attempted to "troubleshoot" what they thought was a comm issue by crowbaring some permissions.
Per IBM, the following files must have there permissions, owners and groups set in the following manner or the system will fail the operation in an attempt to save you from yourself:
-r-sr-xr-x 3 root system /usr/bin/tftp
-r-sr-xr-x 3 root system /usr/bin/utftp
-r-xr-xr-x 1 root system /usr/sbin/tftpd
-r-sr-xr-x 1 root system /usr/bin/rcp
-r-sr-xr-x 1 root bin /usr/bin/rlogin
-r-sr-xr-- 1 root system /usr/sbin/rlogind
-r-sr-xr-x 2 root system /usr/bin/rsh
-r-sr-xr-- 1 root system /usr/sbin/rshd
Hope this helps! Took me forever to work this out the first time it happened because the error message is less than enlightening.