Created attachment 6277 [details] samba.log System: Linux chimera 2.6.32-25-generic-pae #45-Ubuntu SMP Sat Oct 16 21:01:33 UTC 2010 i686 GNU/Linux samba version 4.0.0alpha14-GIT-124abb3 LDAP client Apache Directory Studio Version: 1.5.3.v20100330 (http://directory.apache.org/studio/) backtrace log in attachment.
In order to help us you need to recompile s4 with "./configure.developer" and then run the s4 binary under gdb as follows: "gdb --args ./bin/samba -i -Msingle". Try to run the mentioned LDAP client against the server and when the latter crashes type on the GDB prompt "bt full". Then please paste the whole output here.
The operational LDB module has been broken in this point. The fix should soon land in the main GIT repo. If the crash still happens please reopen!