There is a solution which worked for me running Windows XP SP2 on my computer:

I thought that problem was most probably due to a wrong registration for IE6 SP2 during the Office 2003 SP2 installation procedure. So I decided to reinstall IE6 SP2. However I found that Microsoft does not provide downloading a single installation file for reinstalling IE6 SP2 because it is implemented in the Windows XP SP2 (you need to reinstall SP2 for reinstalling IE6 SP2).
Nevertheless, I still downloaded the small file (481 KB) for reinstalling Internet Explorer 6 SP1 (ie6setup.exe) (I thought after the installation I can download the updates later anyway). After double-clicking on the i6setup.exe I got the message that a newer version of IE6 is installed on my system, so I ran the file again but using the /Q option (simply run the MS-DOS prompt from where the file is located and type “ie6setup.exe /Q”). The version checker is then skipped. I actually worried a bit that now all my settings are going to be overwritten and that it may take an annoying long time to get all the files which I need from upgrading IE6 SP1 to IE6 SP2. But none of it happens. The computer magically worked some seconds and then automatically restarted. After I logged on I found that nothing changed. IE6 SP2 was still present and all my settings were still there. But the problem was solved: finally I can click again on any hyperlink in Word 2003 or Excel 2003 and the Internet Explorer opens automatically as it does before installing Microsoft Office 2003 SP2.
(I assume that running “ie6setup.exe /Q” only a fresh registration for IE6 SP2 is performed but no complete reinstallation which is sufficient to solve the problem.)

You can download the only IE6 installation file here (which is IE6 SP1):
http://www.microsoft.com/windows/ie/...1/default.mspx

Hope it works for you too. Don’t forget to set a system checkpoint before using the method mentioned above. Who never knows…