Hi bash_MS,
Sorry for the late reply, I had to do a few other things first.
Here's an example of a label which gives me this problem:
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
I dragged this label onto my page in design mode. The location where I dragged to was into a cell of an HTML table.
I tried to rename this label to lblTemp in the properties window but when I do that I get the "folderpath invalid" error and the name reverts to Label1. When I rename it in the html view I don't get any error and it works just fine.
I hope you see the problem here.