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Did you try importing a different .mp3 file ?
I was just able to import a different mp3 file. It was much smaller.
Can you please send us the sample audio file which you are not able to import in Presenter 8.
We will take a look and suggest a solution if possible.
Please email the audio file to firstname.lastname@example.org
Adobe Presenter Engg. Team.
I already sent this to Vikas through his FTP site.