Não.
Rules Compendium, page 232:
Immobilized
- The creature can't move unless it teleports or is pulled, pushed, or slid.
Quando um Wizard está imobilizado , ele ainda pode usar o Levitate para se mover verticalmente?
Levitate
Move Action
Effect: You can move 4 squares vertically and remain there, hovering above the ground.
Não.
Rules Compendium, page 232:
Immobilized
- The creature can't move unless it teleports or is pulled, pushed, or slid.
Tags dnd-4e move-action immobilized