It isn’t a limitation of the drive. If Smartburn is turned on, the software may use the Smartburn maximum speed rating as its default. If Smartburn rates media for a 48x burn (regardless of its packaged rating), then the software will try to burn at that speed.
Normally, Smartburn should be left on, primarily to keep media from burning too fast and exceeding its capabilities. It is not a certainty that the burn speed is causing your problem because the failure is caused by a buffer underrun error. This should not be happening at any burn speed, as your burner has buffer underrun protection. Either the software you are using is not supporting the buffer underrun protection or it is not enabled in the software.
In any event, if you want to burn at a lower speed, turn Smartburn off and you should see a variety of burning speeds. If you do not, then the software is properly supporting your Lite-on drive. If you continue to have problems with the software, you might try a different software such as Nero.