I simply did “Help” -> “Check for uppdates” in Eclipse. Then I checked every update possible (I had 2) accepted, waited for the updates to complete, restarted Eclipse and then everything was fixed!
I had some new build errors after the update, though, saying something like:
error: Multiple substitutions specified in non-positional format; did you mean to add the formatted=”false” attribute
I won’t explain the solution to that problem since this post isn’t about it!
However; the solution to that problem can be found in the Google Groups group Android Developers post, SDK 2.3: Get “Multiple substitutions specified in non-positional format” error.