Data Type Mismatch

Hvorfor giver dette:

strSQL = "SELECT navn, belob FROM whistres WHERE slags = 'whist' AND dato = '"& dato &"'"
set rs2 = Conn.Execute(strSQL)


Følgende fejl:

Microsoft OLE DB Provider for ODBC Drivers error '80040e07'

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

/whist/whist.asp, line 24