Contexts not working after migration

I have a site with several contexts. When I migrated the site to a new server, they stopped working. The default context is the only one that works. I get a bunch of errors like this:

[2011-06-12 12:53:19] (ERROR @ /index.php) `[[++my_context_var]]` is not a valid integer and may not be passed to makeUrl()

Anyone have any idea what's going on?

Thanks!

That error suggests that either the Context Setting 'my_context_var' is missing, or you're not really in the appropriate Context when the setting tag is parsed.