If your source media is 1080 50i, that is 1920 x 1080 @ 50 fields per second or 25 interlaced frames per second.
Premiere Elements 11 will set the project preset for you (if you let it) based on the properties of the first video dragged to it Timeline. For now, I would do instead a manual setting of the project preset to
Please see manual set how to in the following
If you are going for Blu-ray disc format on Blu-ray disc, then after your edits, disc menus, head for Publish+Share/Disc/Blu-ray.
But, when you take that same Timeline to DVD-VIDEO on DVD disc, you may or may not have to right click the Timeline video, select Field Options and then Reverve Field Dominance before moving on in the project. This relates to the fact that your source is interlaced video with a field order of Upper Field First but the DVD-VIDEO format uses field order Lower Field First. In the Blu-ray situation, your source is Upper Field First and the Blu-ray burn uses Upper Field First.
Please the above a try on a mini test run basis and then let us know the results.
Sorry for responding so late.
Your suggestion did work properly.
Thanks for the great news that the suggestion worked for you.
Your follow up is important and appreciated by all.
Best wishes as you move forward with your Premiere Elements projects.