Exporting as audio (.wav, .wma etc) in SONAR LE

Sounds like you may be making the same mistake I did when I started.
MIDI tracks are just instructions, they don't make any sounds on their own, they have to be sent to a soft synth track or back to your Juno itself.  That's why when you try to export audio it doesn't let you because if all that's there is MIDI tracks then there's no audio to output.
So you can create a soft synth track and send the MIDI to it.

Or, to get your Juno sounds, you'll have to send the MIDI back to the Juno and have the Juno audio outputs directed back to an Audio track in Sonar.

I know it's a bit confusing at first, but I hope that helps.

Cool! Glad to hear it. Thanks for the feedback (not everyone does that, so it's truly appreciated). Keep coming back to the forum; you can learn a lot just hanging out here because there are really smart, experienced, helpful people here (who've saved my hide more than once).