title: compilation error no relevant source lines
body: <p>just validating a web form and getting the following error
  Everting was working fine until line 34 when I compiled and got this errors.  there are no errors on my IDE 
  I have run a debug and cannot generate or see anything invalid </p>
  
  <p><a href="http://i.stack.imgur.com/k0KZT.jpg" rel="nofollow">enter image description here</a></p>
  
  <pre><code>    &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt;
  &lt;head runat="server"&gt;
      &lt;title&gt;Student Registration Form&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;form id="form1" runat="server"&gt;
          &lt;div&gt;
              &lt;h3&gt;Student Form&lt;/h3&gt;
  
              &lt;table&gt;
                  &lt;tr&gt;
                      &lt;td&gt;First Name&lt;/td&gt;
                      &lt;td&gt;
                          &lt;asp:TextBox ID="txtFirstName" runat="server"&gt;&lt;/asp:TextBox&gt;
                          &lt;asp:RequiredFieldValidator ID="rfvFirstName" runat="server" ErrorMessage="Enter your First Name" ControlToValidate="txtFirstName" ValidationGroup="Submit"&gt;&lt;/asp:RequiredFieldValidator&gt;
  
                      &lt;/td&gt;
                  &lt;/tr&gt;
  
                  &lt;tr&gt;
                      &lt;td&gt;Last Name&lt;/td&gt;
                      &lt;td&gt;
                          &lt;asp:TextBox ID="txtLastName" runat="server"&gt;&lt;/asp:TextBox&gt;&lt;/td&gt;
                      &lt;asp:RequiredFieldValidator ID="rfvTxtLastName" runat="server" ErrorMessage="please enter your surname" ControlToValidate=" txtLastName" ValidationGroup="submit"&gt;&lt;/asp:RequiredFieldValidator&gt;
                  &lt;/tr&gt;
                  &lt;tr&gt;
                      &lt;td&gt;Email&lt;/td&gt;
                      &lt;td&gt;
                          &lt;asp:TextBox ID="txtEmail" runat="server"&gt;&lt;/asp:TextBox&gt;&lt;/td&gt;
                      &lt;asp:RegularExpressionValidator ID="revtxtEmail" runat="server" ErrorMessage="invalid Email Format" ControlToValidate="txtEmail" ValidationGroup="submit" ValidationExpression="^([\w\.\-]+)@([\w\-]+)((\.(\w){2,3})+)$"&gt;&lt;/asp:RegularExpressionValidator&gt;
                  &lt;/tr&gt;
  
                  &lt;tr&gt;
                      &lt;td&gt;Subjects Available&lt;/td&gt;
  
                      &lt;td&gt;
                          &lt;asp:ListBox ID="ltbSubjectsAvailable" runat="server"&gt;&lt;/asp:ListBox&gt;
                      &lt;/td&gt;
                  &lt;/tr&gt;
                  &lt;tr&gt;
                      &lt;td&gt;Subjects Selected&lt;/td&gt;
  
                      &lt;td&gt;
                          &lt;asp:ListBox ID="ltbSubjectsSelected" runat="server"&gt;&lt;/asp:ListBox&gt;&lt;/td&gt;
  
                  &lt;/tr&gt;
                  &lt;tr&gt;
                      &lt;td&gt;Password&lt;/td&gt;
                      &lt;td&gt;
                          &lt;asp:TextBox ID="txtPassword" TextMode="Password" runat="server"&gt;&lt;/asp:TextBox&gt;&lt;/td&gt;
                      &lt;asp:RequiredFieldValidator ID="rfvTxtPassword" runat="server" ErrorMessage="Please enter password" ControlToValidate="txtPassword" ValidationGroup="Submit"&gt;&lt;/asp:RequiredFieldValidator&gt;
                  &lt;/tr&gt;
  
                  &lt;tr&gt;
                      &lt;td&gt;Confirm Password&lt;/td&gt;
                      &lt;td&gt;
                          &lt;asp:TextBox ID="txtPasswordChange" TextMode="Password" runat="server"&gt;&lt;/asp:TextBox&gt;&lt;/td&gt;
                      &lt;asp:CompareValidator ID="cpvChangePassword" runat="server" ErrorMessage="Passwords do not match" ControlToValidate=" textPasswordChange" ControlToCompare="txtPassword"&gt;&lt;/asp:CompareValidator&gt;
                  &lt;/tr&gt;
                  &lt;tr&gt;
                      &lt;td&gt;
                          &lt;asp:Button ID="btnSubmit" runat="server" ValidationGroup="Submit" Text="Button" /&gt;&lt;/td&gt;
                  &lt;/tr&gt;
  
              &lt;/table&gt;
  
  
          &lt;/div&gt;
      &lt;/form&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>