Hi rmiell!
I suspect that your expression is using the wrong property of the combo box.
Try something like the following.
I have rigged up a simple example.
I am inserting a Student Name
From cmbStudentName on my Form
INTO field StudentName in Table1
This code is behind a command button on the form and fires off when the command button is clicked.
Code:
Dim StudentName, StrSQL As String
Me.cmbStudentName.SetFocus
StudentName = Me.cmbStudentName.Value
StrSQL = "INSERT INTO Table1 (StudentName) "
StrSQL = StrSQL & "VALUES (" & "'" & StudentName & "'" & "); "
'MsgBox StrSQL
DoCmd.RunSQL StrSQL
Let me know if that works for you.