Error Message: 
“Document Action Does Not Exist” or “Document Action GT-XXXXX” cannot be found.”

-This error can happen with certain users for one of the following reasons:
1)  They do not have access to the document action custom object. If this user is unable to see the document action tab at top or if they cannot see the specific document action that is referred to in error message on the document action list view (but the user who created it can), then you know that it is being restricted.
How to Resolve: Modify the Salesforce Sharing Rules of that custom object and make sure it is set to “public.” You can go to Setup > Security Controls > Sharing Settings > Document Action > Change to a Public setting.
2) They do not have access to that google doc template.
How to Resolve: Modify the sharing settings of the google doc template that is being used in document action to make sure it is not set to “private.”