perfect, now it works just fine!

thanks a lot,
regards maeck

Thought I would post this here since it's related.
If you have a form within a lightbox and you want to close the lightbox on submit you can add the following to the input tag:
onclick="parent.location.reload();parent.SexyLightbox.close()"
This will close the lightbox when the form is submitted and refresh the main page to show changes if needed.

If you don't need the main page to refresh you can do the same except omitting the reload part such as:
onclick="parent.SexyLightbox.close()"

As an example I have a form to edit blog posts that load in a lightbox.
I have two buttons, one to save the changes and one to cancel.
On the save button I use both the reload and close function, and on the cancel button I just use the close function.