Glad to see it's not just me. I also have the Corporations Overview blocking the screen and it cannot be closed. All I am running is the CP/CBP Beta installed via the auto-installer. I don't even have other mods installed.
Interestingly it didn't come up at first. It only showed up once I had founded a corporation, exited the game, then reopened the game later and loaded the save. Perhaps the reason this issue is less widely reported is that many players don't play all the way to the late game?
You can remove the CorporationsOverview.Lua and .XML until they are fixed.