Hi,
Thanks for purchasing Event Calendar Pro, cool that you're tracking the mojoPortal progress in svn.
1. I just tried this and I confirm it as a bug. It does save the country if you change the country but it doesn't seem to save the state. I will look into this.
2 - 4
I suspect you have some bad javascript in the layout.master file of your skin that is interfering with things. _gat looks like something for google analytics but it does not look like something mojoportal adds to the page for google analytics. I would try with one of the included skins and see if the problem occurs in those skins too.
If you've been upgrading over time I would copy the inlcuded skins from /Data/skins to /Data/Sites/[SiteID]/skins to make sure the site has the newest versions. Then if it works correctly with the included skin, compare the differences in the layout.master vs your custom skin.
Hope it helps,
Joe