So to update VSE you need the patches and hotfixes (there are a few important ones, you cant get these in software center!) checked into a branch (eval, current, previous).
Then you need your agent policy set to updated from a certain branch. lets assume everything is current as thats what i would assume if everything worked for you previously.
Finally you need an update task! it should update all VSE components including patches and updates. you can build this update task in 'menu> policy> client task catalog' then just assign this to your system tree to run once a day/week as needed to ensure everyone keeps up to date.