TMPGEnc changes aspect ratio

[cheeth]

I'm tyring to convert a DivX file to MPEG-1 (NTSC VCD) with TMPGEnc Plus and it keeps changing the aspect ratio from widescreen to 4:3 which distorts the image. I specify 16:9 and it still produces a 4:3 MPEG-1 file.

What am I doing wrong?