Trying to open an archive with archive-mounter (gvfs), the archive gets mounted (shows up as a mounted volume in the side pane), but results in the following error dialogs:
"DBus error org.freedesktop.DBus.Error.InvalidArgs: Mountpoint Already registered" and "The specified location is not mounted"
In my test case, double-clicking an archive defaults to running "Archive Mounter", it causes the described errors, but does make the archive show up as a mounted volume.
While PCManfm can't display the volume when it is clicked on, the archive *is* mounted to: ~/.gvfs/nameofarchive.tar.bz2/
PCManfm tries to open: "archive://file%3A%2F%2F%2Fhome%2Fmyuser%2FDesktop%2Fnameofarchive.tar.bz2/" which it does not know hot to handle.