A couple things to try...
In powerpress settings > media appearance tab, either select or de-select "Display media / links in: WordPress Excerpts (e.g. search results)" and see what happens...
You could turn off the player by selecting disable under Player and media links and just use the short code..
You could also try selecting "yes" under "having theme issues?" and NOT using the shortcode..
Let me know if any of those things make a difference...
Michael Dell
Tech Support, RawVoice Inc.
p:1.877.729.8642
twitter: mgdell
gtalk: mgdell