Reset to default
Trending sort is based off of the default sorting method — by highest score — but it boosts votes that have happened recently, helping to surface more up-to-date answers.
It falls back to sorting by highest score if no posts are trending.
In your error view (command+4, by default, or the 4th tab in the left hand view) you can click the little arrow next to the warning, and it should tell you
Method definition for ‘blah’ not found
I’ve found that sometimes the Log Navigator is the only way to show the actual problem – in at least one case, the error view didn’t help me. To see the Log Navigator, you can use View > Navigators > Show Log Navigator (or ⌘7 by default).