RSS Feed Page Showing Nothing

So, I’m running SlideDeck Lite 2 on WordPress 3.4.1 – the problem is: the rss feed @ https://www.skuff.us/feed doesn’t show any posts. I’ve deactivated the plugin and everything works fine. I also validated the feed with and without the plugin activated. With: there’s an error

XML parsing error: <unknown>:1489:88: not well-formed (invalid token)

Without:

This is a valid RSS feed

How can we solve this?

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