Audio Problems with TMPGenc DVD Author

Hi all.. .new to this whole thing, so bear with me if its a stupid question.
I'm using TMPGenc DVD Author to combine 4-5 different mpegs (VCD's) onto one DVD-R disc. I'm adding the files one by one making sure the audio is recognised in each of them at the appropriate screen. The movies play fine before authoring, but after TMPGEnc DVDAuthor has authored the files into the Video_Ts and Audio_Ts folders, they have no sound. I've burned a cpl of discs now with different clips, the same result.
Do I need to re-rip these mpgs into VOB files and add them that way?

 

To paly in a DVD player, they need to be MPEG2, not MPEG. They should be converted into VOB's, yes.