I frameserved timeline from Premiere to TEMPGEnc via AviSynth plugin, but got absolutely no sound in the resulting MPEG-1.

I used the Premiere plugin for Avisynth 0.25. By the way the advanced settings for this plugin in Premiere export movie dialogue are greyed out, i.e. settings are not accessible. After launch, the plugin says "Loading default settings", then goes to frameserving mode...

Otherwise frameserving looks quite normal, but no sound is rendered.

Am I doing anything wrong?