virt-manager fails to connect to remote server

[Gary Dale <garydale@rogers.com>]

I'm getting a dialogue box message:

Unable to connect to libvirt.
You need to install openssh-askpass or similar to connect to this host.

However, my ssh connection doesn't use a password.

My workstation is running Debian/Wheezy and virt-manager can connect to 
VMs on it. Virt-manager also apparently detects the server, which is 
running Debian/Squeeze, as it shows up as the only option when I create 
a connection to a remote host.

The error dialogue's details box contains the following:

Unable to connect to libvirt.

You need to install openssh-askpass or similar to connect to this host.

Libvirt URI is: qemu+ssh://garydale@TheLibrarian.local/system

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/connection.py", line 1185, 
in _open_thread
    self.vmm = self._try_open()
  File "/usr/share/virt-manager/virtManager/connection.py", line 1167, 
in _try_open
    flags)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 102, in openAuth
    if ret is None:raise libvirtError('virConnectOpenAuth() failed')
libvirtError: Cannot recv data: ssh_askpass: exec(/usr/bin/ssh-askpass): 
No such file or directory
Host key verification failed. : Connection reset by peer


To be clear, I have no trouble connecting to the server using ssh using 
the "garydale" account.

Any ideas?