I have a code in my form, once you type in an employees id it searches a table and auto fills the corresponding data. If the number is incomplete or is not in the table an error window pops up

And below is the code:
The Me.txtEmpName = rec("EMP_NA") is highlighted. I would like in the instance of an incomplete ID or if the ID does not exist, a msg box appears saying that employee id is not valid, please try again. or something along those lines, then it just goes back to the form instead of getting the error message above. Any thoughts?
Private Sub txtEmpID_AfterUpdate()
Dim db As DAO.Database
Dim rec As DAO.Recordset
Set db = CurrentDb
strSQL = "Select * From tblEmpData Where TMSID = '" & Me.txtEmpID & "'"
Set rec = db.OpenRecordset(strSQL)
Me.txtEmpName = rec("EMP_NA")
Me.cboGender = rec("EMP_SEX_TYP_CD")
Me.cboEEOC = rec("EMP_EOC_GRP_TYP_CD")
Me.txtDivision = rec("DIV_NR")
Me.txtCenter = rec("CTR_NR")
Me.cboRR = rec("REG_NR")
Me.cboDD = rec("DIS_NR")
Me.txtJobD = rec("JOB_CLS_CD_DSC_TE")
Me.cboJobGroupCode = rec("JOB_GRP_CD")
Me.cboFunction = rec("JOB_FUNCTION")
Me.cboMtgReadyLvl = rec("Meeting_Readiness_Rating")
Me.cboMgrReadyLvl = rec("Manager_Readiness_Rating")
Me.cboJobGroup = rec("JOB_GROUP")
Set rec = Nothing
Set db = Nothing
End Sub