Trigger works in EM,QA,Adodb but not in access

[PWise]

This is mt table Structure
[StudentIEPID] [int] IDENTITY (1, 1) NOT NULL ,
[StudentID] [int] NULL ,
[CurrentIEP] [bit] NULL ,
[IEPDate] [datetime] NULL

My goal is to insure that each student has only one current IEP.

This my trigger

ALTER TRIGGER SetCurrentIEP
ON StudentIEPs
FOR INSERT, UPDATE 
AS 

If UPDATE(CurrentIEP)OR UPDATE(studentid)

BEGIN

Update StudentIEPs set CurrentIEP=0
from StudentIEPs
inner join inserted on inserted.studentid=StudentIEPs.studentid and inserted.StudentIEPID<>StudentIEPs.StudentIEPID 
and inserted.CurrentIEP=1

END

This works fine in EM,QA,Adodb

But in Access Adp i get this error

Key column informaion is insufficient or incorrect. Too many rows were affected by update

Any Ideas

Thank You