Here's a little tip for developers who encounter "unable to find" errors from Drupal's imagecache module...
Background: As a website developer, I often run a local copy of a website on my own server. I make and test changes there, before promoting those changes to the live website. Usually, my local copy is "incomplete" in that it does not have all the content and data stored on the live site. (Incomplete on purpose, as it would be a lot of overhead to keep all data and files in sync between servers.)