48 KHz is what's needed for dvd. But that's not the bitrate at which the audio is converted to. But AC-3 is fine.
Check if there's a maximum video bitrate.
If the bitrate is not the problem then either the software or the burning or the player is the problem.

How old is your dvd player? Are you using dvd+ or DVD- disks? Are you sure your dvd player can play both formats ok? Are you using 4.7 GB disks or 8.5 GB disks? Do you burn at maximum speed? What speed are the disks capable of & what speed do you burn at? Have you tried burning a DVD-RW disk 1st to see if that plays ok? You might try burning at minimum speed. Might also try a different brand of disk. It's difficult to put a finger on your exact problem. Disk skipping or freezing is generally either due to too high a dvd content bit rate, or the player doesn't like that brand or type or speed burnt at disk or perhaps the player itself needs cleaning.