gvfs-bin is not included in Ubuntu 11.04 by default
I developed a backup software running on Ubuntu at home. To get maximum transfer performance when copying files to remote machine, I use some VFS system commands like gvfs-rm, gvfs-copy and gvfs-mkdir. It's much faster than operating files and folders in ~/.gvfs, which, in my case, can get only up to 500kB/s.
However the first time I used it after I upgraded to Natty Narwhal was a nightmare, I took for granted that those gvfs commands are ready to use but I was wrong.