I am using the Tencoder portable app, (installed on a thumb drive) and got the following message while trying a dvd rip
Assertion v>0 && v
New: Run-Command (Dec 2, 2024), Platform 29.5.3 (Jun 27, 2024)
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TEncoder has not received any updates for 3 years, so you may be running into a DRM issue, I ran into a different DRM-related issue when I attempted a DVD rip to confirm your problem.
Please try using the installed version, to ensure the problem is not with TEncoder itself.