You can not save your video as an AVI from the Mac version of the program.
However, what do you plan to do with your video? There is optimized format for your output, depending on whether you plan to burn your video to a DVD, re-use it in another project, load it to YouTube, etc.
thanks. as of now, most of my 640x480 vids are delivered as a file to clients on fiverr.com. so i just need best quality for size of file with ratio that won't make the original ratio look weird. that's a drag I can't save it as avi. I need to find an editing program that will let me save in more formats (so no need to have to find decent conversion program in case the clients want format I can't save as).
I am not on Mac so don't know the exact screens, but I have read that there is a Mac setting to create a MOV file that is "equivalent" to DV AVI on Windows
The Tutorial Links Page http://forums.adobe.com/thread/1275830 has links about several Sharing options
Premiere Elements FAQ List (2 pages of FAQ as of September 2013) http://forums.adobe.com/community/premiere_elements/premiere_elements_faq?view=all
Premiere Elements TIPS List (6 pages of Tips as of September 2013) http://forums.adobe.com/community/premiere_elements/premiere_elements_tips?view=all
I would recommend you use Publish & Share/Computer/AVCHD with the preset for YouTube SD or HD to output your finished video. Both these outputs should produce terrific looking video on Fiverr.