as an aside, you can do
If IsNull(Me.combo12) Or Me.combo12 = "" Then
as
If nz(Me.combo12,"")="" Then
try typing the dlookup in the immediate window, like
?DLookup("strEmpPassword", "tblEmployees", "[lngEmpID]=12")
it will almost certainly be a text/long error, dlookups are fiddly and...