"Failed due to exception from main class." pop-up error dialogue

[metacoin]

This error popped up when opening a lighthouse project on Windows 7 Professional 64-bit.

The file I opened was project-germinate.lighthouse-project, which was downloaded from a link on a reddit thread.

I am not sure if they will change this file, so I can provide the sha1 checksum:
1b17529a1b9baa36b2ef61b3aa3d86ebb0014040.

I can still read the project description and there is no other noticeable negative effect.