RegularExpressionValidator dsn't work

I have a problem with RegularExpressionValidator when I want to validate en emailAddress,
I'm trying to use this:
<label for = "EmailAddressTextBox">Email Address:</label>
<asp:TextBox ID="EmailAddressTextBox" runat="server"
Text='<%# Bind("EmailAddress") %>' MaxLength = "50" />

<asp:RequiredFieldValidator
ID="RequiredFieldValidator3" runat="server"
ErrorMessage="Var god ange kontaktens e-mail adress"
ControlToValidate="EmailAddressTextBox"
Display="Static" Text="*"
ValidationGroup="insert" SetFoc ...