Did you enter the last opened area, get a conversation with Astarte or the demon, and return to the main section of the homestead through the portal?
Was Zixzax at the start of the homestead, by the statues, by a portal or the weaver? Did he have his regular dialogue options or was he urging you to 'leap through'?
If he was by a portal or near the start, approaching an inactive portal can trigger a dialogue with Zixzax and open the portal. If he was near the statue, you may be able to click on it to proceed, if Zixzax doesn't react to your approach.
If the problem is with Zixzax, killing him can reset his status, and get him opening portals again. That is feasible starting about level 12 or 13, depending on your party build.
