Hello Rehman,
If the client is a managed client and you've uninstall liveupdate then I would suggest following things :-
1] uninstall liveupdate
2] delete liveupdate folder from C:\Documents and Settings\All Users\Application Data
3] install liveupadate
4] repaire SEP from Control Panel > add/remove program > Repair
This would re-register liveupate with SEP and it should take update from SEPM.
Please update the status,
Cheers!!