In Windows 2003 and Windows XP, you are unable to view the data in files with an extension of CHM (Microsoft Compiled HTML Help file) from a network resource. Security patches prevent this and you get an error that says:
Navigation to the webpage was canceled
This program cannot display the webpage
In order to make this work, you have to add the UNC path to the server where the files are stored to your trusted sites in Internet Options within Internet Explorer. Here’s how:
1. Open Internet Explorer and click Tools > Internet Options.
2. Click the Security tab.
3. Click Trusted Sites.
4. Click Default Level.
5. Set the Allowed levels for this zone to Low.
6. Click Sites.
7. Type the path to the server where the CHM files are. In this example, the server computer name is techpoint, so we type \\techpoint and click Add. You could also add the name of the domain.
8. Click Close.
9. Click OK on the Internet Properties dialog.
Close Internet Explorer and you’re done. You should now be able to view the content of CHM files when you open them.