Hi Jason,
There seems to be some problem with deeplink v 10.0.4, I was not able to find required jar files in user library, So quick fix will be to use any previous version to above mentioned version like 10.0.3 or 10.0.2 until it get fixed by developers.
check duplicare jars or jars with same name and 1.1 / 1.2 at the end and keep the latest one. could be userlib chenanigans
This looks like the StartDeeplinkJava Java Action in the Deeplink module may have been deleted and recreated. It is returning the standard placeholder error message that a newly created Java Action has by default.
I would suggest you reinstall the Deeplink module from the Marketplace as it should recreate all the files it needs.
Good luck!