RE: Issue with Zetadocs Express and ClickOnce Deployment
You can find in the installation doc a part that says...
Now that we have made the necessary modifications to NAV we can roll Zetadocs out across the other client machines. To do this simply log onto client machine in question with an account with admin rights and follow the instructions in section 1.1 to run the Zetadocs Express Installer program. This will add all of the necessary components onto the machine to enable it to utilize the Zetadocs functionality. You should perform the brief tests in section 4.34 to process the four warnings describe above, it is also recommended that you perform the other tests in section 4.1 to confirm that Zetadocs is operating as expected.
Which basically suggests you might want to try to add the same add-ins you have added in the service tier, also within the add-in folder in the client's folder (typically in C:\Program Files (x86)\Microsoft Dynamics NAV\71\RoleTailored Client\Add-ins).
Can you try that and let us know how it goes?