Refresh Thumbnails not working

[Avishai]

Hi, I've been using Paperclip in my Rails 2.3.4 app on Passenger on OS
X in development. Uploading new images works totally fine with the new
parameters. However, rebuilding the thumbnails via the console doesn't
work at all:

rake paperclip:refresh:thumbnails CLASS=Photo
rake aborted!
You have a nil object when you didn't expect it!
The error occurred while evaluating nil.read

Does anyone know how to make this work?

Thanks,

Avishai