Hi Cloud Geek,
I have done some research on the error message “RPC Error 8439 : The distinguished name specified for this replication operation is invalid. There was an error calling _IDL_DRSGetNCChanges”. According to the KB article http://support.microsoft.com/kb/2867278, the issue can be caused if Windows 2003 server domain controllers handle certain scenarios unexpectedly. However, this issue should have been resolved by a previous Dirsync client version 6411.0009. Since you have installed the latest version of Dirsync (version 1.0.6635.43) and the issue persists, it is a little strange. Therefore, I have sent you a private message to collect detailed information such as tenant domain name for further research. Please check the private message by clicking Private messages under Your details on the right side of the community site.
We will do our best to help you to resolve this issue. Your patience and cooperation is appreciated.
Thanks,
Mindy Pan