BTW, anyone using ROM Collection Browser who's just upgraded to the latest XBMC beta and found that the list of ROMs is completely blank:
Open up C:\Users\[username]\AppData\Roaming\XBMC\addons\script.games.rom.collection.browser\resources\lib\gui.py and find the following line, which appears twice:
self.addItem(item, False)
In both occurrences, change it to simply
self.addItem(item)
You don't need to restart XBMC, but if you've got ROM Collection Browser open, right-click out of it and then reopen it. That will get the list to reappear.
If you find that it throws an "Unimplemented method" error for executehttpapi when you try to launch a game, open up launcher.py in the same directory and replace all instances of "executehttpapi" with "executeJSONRPC". (Same as above: you don't need to restart XBMC, but you do need to restart ROM Collection Browser for the changes to take.)
Thanks to versus for posting the gui.py fix and fmonaca for posting the launcher.py fix on the XBMC forums.
(And yes, I am posting this at 12:30 in the damn morning. You know how sometimes you have a thought on how to fix a vexing computer problem and know it'll be gone by morning?)