What computer operating system and what video card/graphics card does your computer use?
What is your burn to DVD - DVD-VIDEO standard or widescreen on DVD disc (regular or double layer) or AVCHD on DVD disc (regular or double layer)?
What is the degree of complexity of the Timeline content? Shake Stabilization applied to Timeline content?
Let us start here and then decide what next based on the details in your reply.
Any questions or need clarification, please ask.