I spent a day figuring this out and thought I would share the answer.

Problem: Premiere Elements 9 does not provide an option for burning AVCHD movies to DVD discs. If you don't have a BD burner, or want to use cheap DVD discs, you have to use the following work-around.

Step 1. Prepare your movie in Premiere. Then Share -> Computer -> MPEG -> H.264 (pick the one that matches your movie) ->Save. The result is a single file called *.m2t

Step 2.Generate AVCHD file structure. To play in a BluRay player, the Premiere movie file (*.m2t) has to be placed within the correct file structure (AVCHD). This file system can be generated using tsMuxer.exe (free download @ www.smlabs.net/tsmuxer_en.html ). The muxing process also changes how the video and audio streams are arranged in the movie file (but there are no changes to the video pixels themselves; processing takes only a couple minutes). To use tsMuxer: Ensure that “Input” tab is selected at top; drag and drop the Premiere movie file to tsMuxer “Input Files” window; set “Output” to AVCHD disk; “Browse” to select your output folder; use defaults for all other settings; click “Start Muxing”. Result is a *.m2ts video file plus the full AVCHD file structure (including all the required supplemental files). SPECIAL NOTE: tsMuxer does not accept the *.m2t file generated by Premiere directly. A simple work-around is to rename the Premiere file to *.ts before dropping into tsMuxer. I’m not sure why this works, but it does.

Step 3. Burn the AVCHD to DVD disc using ImgBurn (free download @
www.imgburn.com/index.php?act=download) From the start page, select “Write files/folders to disc”; then click the “Browse for a folder” button and select the folder containing your full AVCHD structure; select “Device output” via toggle button; uncheck “Verify” box; under the Options tab, select “File System” = UDF and “UDF Revision” = 2.5; use defaults for all other options; click the “Build” button to begin the burn process. SPECIAL NOTE: Although tsMuxer produces a fully compliant AVCHD file structure, it will not play on all BluRay players when burned on a DVD disk. Some experimentation may be required. On my LG player I had to delete several folders and files before burning to generate a format that would play (happens to be identical to the file structure on my Canon Vixia M30):
o Root directory includes BDMV only (i.e., delete Certificate folder)
o BDMV folder includes Backup, Clipnf, Playlist, and Stream folders only (delete the others), plus the following 2 files: index.bdmv and MovieObject.bdmv
o Backup folder: delete the BDJO folder

Step 4: Enjoy your movie. Depending on your bit rate setting you can get from 15 min to an hour of AVCHD on a 4.7GB disc. Note that the default setting in Premiere provides a very high bit rate setting (higher than I use on my camera).