Please confirm if you have the latest version of QuickTime installed on your computer and that you are running the program from a User Account with Administrative Privileges or Run As Administrator. If you are and still have the problem, then please read on:
On what computer operating system is your Premiere Elements 11?
What are the properties of what you have put on the Expert view Timeline of the project...video and audio compression, frame size, frame rate, aspect ratio, file extension, duration....?
What have you or the project set as the project preset for this project? Does it match the properties of your source media? If you are not sure of the project settings, please tell us what it says for Edit Menu/Project Settings/General Editing Mode, Timebase, and Frame Size.
How do you have your Scratch Disks set up (See Edit Menu/Preferences/Scratch Disks.) Are they directed to a hard drive save location with enough free space to accept them? Is your computer optimized..defragmented, no pile ups of preview files and conformed audio and video.
What were your export settings...please confirm:
PAL DVD Standard
If that is correct, did you change any of the settings under the Advanced Button of the preset?
Let us start here and then decide our troubleshooting strategy.
Add on...I forgot to ask, Is this "it worked before but now" issue or is this an issue where "it never worked before"?
Welcome to the forum.
Along with the answers to ATR's questions, you might want to look at this FAQ Entry: http://forums.adobe.com/thread/792580?tstart=0
It starts with a checklist for getting PrE running at its best, then goes into some tips on tuning up one's computer and OS, to run PrE best, and then goes into many links on troubleshooting, with more links to tools, to help in troubleshooting.