Same problem here:
[Error] XMLHttpRequest cannot load safari-extension://com.evernote.safari.clipper-Q79WDW8YH9/70a9eaa7/_locales/de_ch/messages.json. Cross origin requests are only supported for HTTP.
a (port.js:2:2919)
_getL10nData (port.js:2:3802)
getMessage (port.js:2:3972)
getExtensionID (Browser.js:2:109)
initBrowser (Browser.js:2:758)
Globaler Code (Browser.js:2:8675)
I have to uninstall the extension :-(