I pooched one of my RSS feeds

Hi,
I’ve been trying to customize my RSS feeds to work as podcast feeds and inserted a code snippet I found via Google which screwed up this one RSS feed, but none of the others. I’ve reverted my functions.php file, but that didn’t revert the error. Going to the feed’s URL prompts me to “Open With” instead of displaying the same way Firefox displays RSS URLs.

The related PHP Warning is:

<br />
<b>Warning</b>:  call_user_func_array() expects parameter 1 to be a valid callback, function 'my_pre_get_posts' not found or invalid function name in <b>/....../web/evrn.net/nua/wp-includes/class-wp-hook.php</b> on line <b>286</b><br />
<br />
<b>Warning</b>:  call_user_func_array() expects parameter 1 to be a valid callback, function 'my_pre_get_posts' not found or invalid function name in <b>/....../web/evrn.net/nua/wp-includes/class-wp-hook.php</b> on line <b>286</b><br />
<br />
<b>Warning</b>:  call_user_func_array() expects parameter 1 to be a valid callback, function 'my_pre_get_posts' not found or invalid function name in <b>/....../web/evrn.net/nua/wp-includes/class-wp-hook.php</b> on line <b>286</b><br />

Any clues to what’s going on here is appreciated. Thanks

The page I need help with: [log in to see the link]