Since installing 5.5, I've been having problems installing Auto-Nav, when I select beneath a particular page, it doesn't give the "choose page" link. If I choose save even though I didn't choose a page it takes me to a blank page with an error such as this;
{"aID":"1214","arHandle":"menu","cID":"426","error":false,"bID":"1059"},
if I go back in my browser and choose edit Auto-Nav I can now see the "choose page" link when I select it takes me to a page that shows:

Sitemap
Search

Full Sitemap One Level Only

but it does not show my full sitemap to choose the appropriate page. I cleared my cache but there is still no change.

Any ideas about what may be happening?