The lastest version of OMV isn't 1.9. It's 2.x. In fact, as of yesterday, 2.0.7. http://www.openmediavault.org/?p=1682
I'd update and see if this fixes your issue.
You should not upgrade to 2.x if you use the zfs plugin. The GUI does not work in extjs5 which is used in 2.x. When I press ZFS tab in the left menu nothing happens. To me it seems like the gui is hanging somewhere and just times out.