Problem with the creation of html output in FrameMaker structured 12

Hello !

I have a problem when I try to create an HTML output in structured FrameMaker 12.
It only creates the file "index.html", but my topics (tasks, references, concepts) are not converted. So when I open the file "index.html", it shows the table of content but when I click a link, it does not work.

However, the creation of PFD output works perfectly.

Does anybody knows where the problem could come from?

Thank you