Welcome to the forum
You don’t say whether you’re burning your .avi files as data discs, or converting them into DVD-compliant format.
If it’s the latter, and given that the original .avi’s play fine on the PC, then I would suggest trying a different software to start with - perhaps a free option like DVDFlick…or a pay option like ConvertXtoDVD, which I use and have never had a problem with.
Also, please tell us what speed you’re burning at - it may be that a medium speed like 8x will help, if you’re burning at the disc’s max supported speed.
Hope that helps.
EDIT: LOL! Kerry, you sneaky devil, you beat me to the punch