Marketpress problem: Product category pages go ugly with Catalyst


(I´m new to Marketpress so please bear with me, and link me to the appropriate answer if this is an old issue!)

Here´s the deal: When I try to display a product category page, I just get a single image and a bunch of unformatted, unseparated text. Info from all the products in the category is there, only its completely garbled. In the output HTML it´s all a single paragraph, like this:

<p>Sportskon MaxPrice: from 150 krChoose Option &raquo;Partydojan HindenburgPrice: from 499 kr399 krChoose Option &raquo;Finskon AngelikaPrice: 990 krFestskon SnövitPrice: from 350 krChoose Option &raquo; <a class="excerpt-read-more" href="">Read more »</a></p>

I would have wanted something more like this (this uses the grid shortcode plugin, a list would be ok too):

I would have assumed this was a Catalyst problem (the theme I use) since it does not happen with the Simplemarket theme. However, since the HTML looks so weird, I can´t see it as being conflicting/overridden CSS.

I have done no custom coding at all yet, everything is pretty much out of the box.

All ideas welcome!