I have upgraded two different server from 5.0.14 to 5.0.20 without any problem.
When I try to upgrade to 6.0.2 I get the same error on both server:
It convert MySQL schema to 63 without problem, and after when it start to migrate LDAP crash with the error:
"Migrating ldap data...slapadd import failed.
UPGRADE FAILED - exiting"

If I restart the installation it crash in the same point, in the log I dont have any further information about the error.
I was obliged to uninstall the failed 6.0.2 and restore 5.0.20 from backup maked by me previously.

I have followed the two wiki:
- Optimizing 50 to 60 LDAP upgrade - Zimbra :: Wiki
- Managing Customized BDB configurations - Zimbra :: Wiki
without result, I dont use Samba and I dont have Samba.Schema. What I'm missing? Some .schema or some .ldif to edit/copy/upgrade for make it compatible with the new schema of 6.0.20?

Thank you for your support