I just created a webpart that has a simple input box in it that posts
back to the page. All in the webpart is working fine. But on this same
page for navigation I have a ASP:Treeview setup that is using a custom
sitemap file.

When I first load the page it all works fine. But once I submit the
webpart form, the message: 'There was an error in the callback.' comes
up. Instead of the full Treeview. Whats odd is that the First level of
the Tree loads. But when I click to expand the tree, it just continues
to write that error out instead of expanding it. Is there a particular
way I should be posting this form to the page?