A PLE is at the individual's learning end, usually working in Web 2.0, to bring knowledge to him/her. Perhaps using many tools/systems. Have a look at Kathryn's presentation to understand the variety. But do you see the point? A PLE is under the control of the user and s/he selects several tools/systems to bring the knowledge to him/her.
A Course Management System (CMS- Blackboard, Angel, Sakai [Sakai calls their system a Collaboration and Learning Environment], Moodle, etc) is at the other end. Produced by the university or school, controlled by them. But then used as one of the PLEs by the user.
PLEs - flexible, user-controlled, messy.
CMS - inflexible, out of user-control, very compartmentalised.
What needs to change?
Could a fairly complete VLE/CMS be produced into a PLE, perhaps as gadgets/widgets? So that on one "tab" of the PLE the set of tools needed for a particular course could be called up? So that the discussion forum appears there, as well as the course outline, the links to reading, etc?
(Am using CMS and VLE together since, although slightly different, CMS can have a different meaning - as in website design)