Data type mismatch in criteria expression

I'm getting an error that I don't know how to deal with.

I think the error has something to do with the coding in my
AfterUpdate event of combo28 which is as follows...

Private Sub Combo28_AfterUpdate()
  Combo36.RowSource = "SELECT [Location ID].[Location Name], [Location
ID].[Location Code] FROM [Location ID] where [Location ID].[Vehicle
ID] = " & Combo28.Column(1) & ";"
  Combo36.Requery
End Sub

When I click on combo36 I get the error message, "Data type mismatch
in criteria expression."  I thought maybe the problem was that the
Vehicle ID of one table was numeric while the other was text.  But
they are both set as text as I would like them to be.  There's even an
established relation****p between the Vehicle ID's of each table (the
two tables are "Vehicle ID" and "Location ID").  So I have no idea why
the Vehicle ID from combo28.column(1) (this combobox pulls it's
choices from table "Vehicle ID) does not match up with the Vehicle
ID's from the table "Location ID"

Any thoughts?  (And any bit of information is helpful!)

Thanks so much!