libqt4-opengl cannot be installed as it requires earlier versions

Binary package hint: libqt4-opengl

Prevents installing VirtualBox.
Maverick AMD-64. Fully up to date.

apt-cache policy libqt4-opengl
libqt4-opengl:
  Installed: (none)
  Candidate: 4:4.7.0-0ubuntu4
  Version table:
     4:4.7.0-0ubuntu4.1 0
        100 /var/lib/dpkg/status
     4:4.7.0-0ubuntu4 0
        500 http://gb.archive.ubuntu.com/ubuntu/ maverick/main amd64 Packages

sudo apt-get install libqt4-opengl
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 libqt4-opengl : Depends: libqtcore4 (= 4:4.7.0-0ubuntu4) but 4:4.7.0-0ubuntu4.1 is to be installed
                 Depends: libqtgui4 (= 4:4.7.0-0ubuntu4) but 4:4.7.0-0ubuntu4.1 is to be installed
E: Broken packages