Feed Doesn’t Validate

I’m having a problem with my feed. I can’t find a fix for this error in the forums. Any advice would be much appreciated.

http://www.sustainableconsciousness.com/?feed=podcast

This feed does not validate.

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line 15, column 11: XML parsing error: <unknown>:15:11: not well-formed (invalid token) [help]

<language></language>