The project specs have little effect on the exported movie format - unless you actually writing to a tape target.
I create/work all my projects as DVD format wide screen - and then simply export the movie as the deired target type.
What is going to determine the success of the export, is the selected export type and its particular parameters.
For example - you cannot export an MPeg4 movie for DVD output if you have Mpeg 2 audio slected.
Try setting the project general/video/audio vales to the desired output type - (of course save your project under a new name - always save early and save often with backup versions).
Don't bother transfering the preview files - just generate em again.
Take some screen shots of the General, Video and Audio tabs of the project and post em to help with the support.
In the worst case scenario, you may have to convert your Video source files if you run into troubles (especially with DVD authoring software hooked into your Adobe Premiere install).
Either way - the timeline edits and changes, video transperancy, motion and effects, transitions and audio panning, volume and stills should be preserved on the timeline - you would just need to regenerate any preview files in your 4:3 output format.