Cannot Get AV1 Render TO Work Vegas Pro 23 (302)

I am using the trial version license. I purchased a license last year and I know 2026 build is the newest one. Last years licensee will not take. I wanted to try the 2026 build as a trial before I purchase the newest version.

I installed the latest Windows Voukoder version 3.0.15, and FFmpeg 8 GPL. When I go to render a AVI NVIDIA scene I get the error dialog box shown below. Voukoder will render Prores_KS, and Nvidea H264, after a slight pause before the render begins. I tried the built in AV1 render template in Vegas and that rendered fine. I am selecting the scene before I render. I have the latest Nvidea Studio drivers installed. I also posted a log file. Thanks

2026-01-05_09-36-52.log

Thanks, rendered to MP4 and that worked. Thanks for the quick response. It is hard to find good customer care now a days. I just purchased Voukoder Pro 2026. Thanks for all of your hard work on this project.