Gmail Filesystem provides a mountable Linux filesystem which uses your Gmail account as its storage medium. Gmail Filesystem is a Python application and uses the FUSE userland filesystem infrastructure to help provide the filesystem, and libgmail to communicate with Gmail.
There is a problem with gmailfs in Gutsy or rather libgmail
HTTP Error 400: Bad Request
Fortunately the fix is easy (or workaround until the libgmail package is updated).
$ sudo easy_install --upgrade libgmail