Second title created using ConvertXtoDVD is corrupted

I used CXD to create a DVD from two video files - 1st one is an avi and the 2nd is in mpeg. At the end of burning the DVD, CXD reported a finalization error. When playing the disc in a standalone player, the 1st title played fine. However, the 2nd is blocky and stopped after a few seconds.

I played the files in the VIdeo_TS folder created by CXD on my HD directly, both titles played ok. But when I burned this folder to a DVD, I experience the same blocky 2nd title, but the 1st one is ok.

Both videos are in NTSC format and the ouyput is also set as NTSC.

Any suggestion how I can get round this problem?