LDAP add fails with Protocol Error

[Alexander Hartner <alex@j2anywhere.com>]

After generating an LDIF file using ldapsearch having a direct fast  
connect to the LDAP directory, attempt to re-import the file have  
succeeded while being on the local network. However attempt to import  
the same LDIF file over a WAN connection fail with the following error:

ldapadd -c -D "..." -w ... -x -h ... -p 389 -f test2.ldif
adding new entry "..."
ldap_add: Already exists (68)

adding new entry "..."
ldap_add: Already exists (68)

adding new entry "..."
ldap_add: Protocol error (2)
        additional info: no attributes provided

adding new entry "..."
ldap_add: Already exists (68)
..
adding new entry "..."

adding new entry "..."
..
adding new entry "..."
ldapadd: update failed: ...
ldap_add: Can't contact LDAP server (-1)
..

All messages after this file with the same error (-1).

It seems that the slower connection is causing a Protocol error which  
results in LDAP falling over, or at least becoming un-available.

Any ideas what could be causing this problem and what I could to  
address this.

Regards
Alex