I'm also wondering if you can try to add some temporary test HTML to the General.aspx file to see if that change is visible. For example, after line 14 of the file:
<asp:Content ID="cntBody" runat="server" ContentPlaceHolderID="plcContent">
<!-- Debug Start-->
<h3>Debug Test Code</h3>
<!-- Debug End -->
<asp:Panel ID="pnlContent" runat="server">
Adding this debug HTML should display the words Debug Test Code under the save button.
If the HTML is visible, then it might be an issue with your back-end logic. If it is not visible, then then is could be something to do with your file system reference.
Also, is this a web application and are you building it? Or is it a web site?