Does premiere elements trial version have some limitation on file size / audio ? I converted an avi of about 1gb to iphone format using trial version, and there's no audio in it , although I can view it on iphone just fine.
Another problem I faced with trial was that the app interface sometimes freezes. I tried converting an mpeg of about 600 MB to iphone format, the interface suddenly froze inbetween. The conversion was happening in background: I could see the converted file growing in size. I left it on overnight and next morning, theUI was still stuck at same place, even though the file was all converted and I could view it in itunes.
The only limitation on the trial is the "Made in PrE Trial" banner on Export/Share. Otherwise, it is exactly the same as the full-paid version.
Now, there could be limitations with either your system, or with your Assets and Project Preset. This ARTICLE will give you tips on the types of info that can be very useful.
Can you tell us about your system - full details, including things like your HDD's, their size, format type, speed, free space and how allocated.
Please tell us more about your source files. AVI, MPEG, MOV, etc., are but wrappers, and can contain all sorts of "stuff." this ARTICLE will give you more background.
Then, can you give us the full details of all of your Export/Share settings? Be sure to give details on all aspects (tabs), including Multiplexing.
Screen-caps can be very useful for this, as it will save you a lot of typing.