After setting up an external browser preference to be used by ISE applications, I see that the correct browser is not used by Timing Analyzer.
To work around the issue:
1. Set the following environment variable:
2. Open Timing Analyzer and under the Help Menu, select Help Topics.
3. Enter the browser command line in the pop-up dialog and then press enter.
4. Quit Timing Analyzer and unset:
The correct browser should now be opened by Timing Analyzer. This issue is resolved in ISE 8.2i.