SQL Problems

Having a small problem with a SQL statement and was hoping someone could help out. 

Thanks

This is the error I get:

[Microsoft][ODBC Microsoft Access Driver] Data type mismatch in criteria expression.

Code:

 strUserName = Session("userName")

 Set rsEmail = Server.CreateObject("ADODB.Recordset")

 strSQL = "SELECT email, username FROM tblUsers Where username = " & strUserName

 rsEmail.Open strSQL, adoCon

The strUserName is correct I checked that with a Response.Write.  don't know if this helps but username isn't the first column or the primary key but there can't be two of the same usernames in that column.