I would like to add a TOC entry that linked to a registration website is this possible or ist the another way to get a webpage to lauch from within the presentation?

Hi Mark,

Th functionality you are looking for can be done with the help of a small tweak.

You can set the option of on slide enter as redirecting to the registration website, so that when user clicks on that particular slide link in TOC, User is redirected to the website.

Regards,
Zeeshan

Did you try to use the Interaction 'Web Object'? It has to be done on a slide, you cannot do it directly in the TOC.