Of further note, finally figured out how to identify the server version this is running on:
===== Tableau Server Command Line Utility -- Version 7000.12.0330.1859
Does anyone else actually use tabcmd? to get workbooks?
Well for anyone who came here hoping for an answer. In my case this was permissions.
The 25 reports that "worked" all had an admin group set up on them that included the automation account. Whereas the 5 that "failed" with 404 were all older reports that did not have the admin group added but had all the individual users in our team added, they did have a viewer privilege group added though so the automation account could see .PNGs etc.
I only figured this out after looking in more detail at the .html file that it did download via tabcmd. The html was actually also incomplete and it included the 404 error and a message about permissions.
My own trouble shooting list now includes, in no particular order.
Tabcmd for twbx fails:
Attempt tabcmd against a .png of a view, check result
Attempt tabcmd against .html, check result
Review tabcmd logs ( %APPDATA%\tableau )
Attempt workbook download from active session via URL.
Hi Andy! I am also planning to use tabcmd to pull down the workbooks. This post has helped me know where to start. Thanks!