UpdatesDeployment - another job is still in progress

Hi there

I have 1 secondary site (out of around 70) that clients are not installing their Windows Updates correctly.  The software updates icon appears in the system tray and when any user at the site tries to install the available updates, the UpdatesDeployment.log file on the PC contains the following lines:

    InstallUpdates Initiated by user

    Install not allow as another job is still in progress.

    InstallUpdates failed, error 80040703

    Failed to initiate installation of updates, error = 0x80040703

    EnumerateUpdates for action (UpdateActionInstall) - Total visible updates = 16

I am not able to determine what other job is still in progress, but does anyone know of a way to do this?  And to hopefully cancel it if possible?   Every other site with the same deployment works properly.

Thanks in advance

John