Are you saying the cube no longer switches desktop and that using the mouse wheel or clicking the pager simply switches desktop in the usual way?.
You have a glut of virtual desktops on the one desktop......... if you follow me

Under CCSM General Options > Desktop Size > Number of Desktops - Set this to
1That should restore normal service.
Another less simple way is to keep right clicking the pager and selecting remove last virtual desktop until normal function comes back.
I chewed my way through a lot of pencils over this same issue.
