usrmgr.exe. When logged in as root, trying to assign rights to users fails, access denied. LDAP backend(other backends not tested). If you cant reproduce i'll get traces/tcpdumps soon. log level 10: http://dmarkey.com/~dmarkey/log.galway
User rights assignment should be fine in master and v3-4-test now, can you please test ?
Fixed for next Samba 3.2 release (by reverting to previous behaviour).