Error... BC30451: Name 'eventPurpose' is not declared.

For some reason when I use checkboxes and groupName it states it isn't declared.  Any ideas?
Thank you :)


eventPurpose.Text        = ""


<tr>
<td><asp:CheckBox ID="lecture" Text="Lecture" groupname="eventPurpose" runat="server"/>
  <br />
<asp:CheckBox id="dance" Text="Dance" GroupName="eventPurpose" runat="server"/><br />
<asp:CheckBox id="breakfast" Text="Breakfast" GroupName="eventPurpose" runat="server"/><br />
<asp:CheckBox id="luncheon" Text="Luncheon" GroupName="eventPurpose" runat="server"/> </td><td><asp:CheckBox id="dinner" Text="Dinner" GroupName="eventPurpose" runat="server"/><br /& ...