Permission denied

When running rake themes:install I get the following:

Cloning into 'limechat-whisper'...
remote: Counting objects: 21, done.
remote: Total 21 (delta 0), reused 0 (delta 0), pack-reused 21
Unpacking objects: 100% (21/21), done.
Checking connectivity... done.
Cloning into 'mattg'...
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
fatal: clone of '[email protected]:mattg/LimeChat-Themes.git' into submodule path 'mattg' failed

Haven't used Limechat in a while, might be a bit before I get to look at this.