This is because the new, longer list of international shipping options is now too long to fit into the database "set_function" field properly
There are two solutions, one is to alter the set_function field to a longer data type (such as blob). The other (which I opted for) is to cull out some of the shipping options you know you're never going to use from the long list, so that it's within the allowed character length for "set_function"
Here's what I used for the value of "set_function":
tep_cfg_select_multioption(array('Global Express', 'Express Non-Doc Non-Rect', 'Express Mail Int', 'Express Mail Int Flat Rate Env', 'Priority Mail Int', 'Priority Mail Int Flat Rate Env'),