default mail client problem

I have just installed Outlook-Novell Groupwise connector (running XP SP2 prof
and outlook2003) and have the problem that clicking mailto-links and
sendto-links don't work anymore. I have tried to set the default
mailprogramme to Outlook in IE, but it doesn't work. I found the hint
http://www.slipstick.com/config/defaultmailer.htm, to correct the path for
the filetype "URL:MailTo Protocol" in the filetypes dialog. However, I do not
have any "URL:MailTo Protocol" entry among the filetypes. Trying to make a
new is above my abilities: it asks for a range of "associated file type"s
among which I can find no clue.
I also tried to do as suggested in
http://support.microsoft.com/?kbid=813745, without any effect. Looking in the
registry, HKEY_LOCAL_MACHINE\SOFTWARE\Clients\Mail, there is a subkey
"PreFirstRun" with the value "Either there is no default mail client or the
current mail client cannot fulfill the messaging request. Please run
Microsoft Office Outlook and set it as the default mail client.*Microsoft
Office Outlook"

Any idea what to do?
Thure