Can't Solve with this error

SELECT MenuID,MenuName,ParentID,
IsNull((Select 1 As Allow from [tb_GE_UserLevelMenu]
Where MenuID = A.MenuID AND SysID = " & UserLevelID & " ),0)
As checked FROM tb_GE_Menu As A ORDER BY SrNo

<pre>

Msg 512, Level 16, State 1, Line 1
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.