"Error - Parser Error: Unknown Server Tag '<TagName>'." error message when you view an .aspx page in Design view in FrontPage 2003

In Microsoft Office FrontPage 2003, when you open an .aspx page in Design view, you may receive the following error message: The placeholder for the user control does not appear as expected on the page.

This problem occurs if the .aspx page contains one or more user controls that are located in <asp:Panel></asp:Panel> tags. FrontPage 2003 incorrectly detects user controls that are located in <asp:Panel></asp:Panel> tags.

To work around this problem, replace the <asp:Panel></asp:Panel> tags that contain user controls in the .aspx page with <div></div> tags. The <asp:Panel> tag is rendered as an HTML <div> element. To replace the <asp:Panel></asp:Panel> tags in the .aspx page with <div></div> tags:

1. Open the Web page that you want to modify.
2. At the bottom of the page, click Code.
3. On the Edit menu, click Find.
4. Click the Replace tab.
5. In the Find what box, type <asp:Panel>.
6. In the Replace with box, type <div>, and then click Replace. Replace all <asp:Panel> tags that contain a user control.
7. In the Find what box, type </asp:Panel>.
8. In the Replace with box, type </div>, and then click Replace. Replace all </asp:Panel> tags that contain a user control.
9. On the File menu, click Save.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

FrontPage 2003 does not support design-time preview of user controls. When you view an .aspx page in Design view and the Web page contains one or more user controls, a box that contains the tag prefix and the tag name appears as a placeholder for the user control. However, if the user control is located in <asp:Panel></asp:Panel> tags, FrontPage 2003 does not correctly detect the user control, and you experience the symptoms that are described earlier in the "Symptoms" section.

For more information about FrontPage 2003, visit the following Microsoft Web site: