first - thanks for the plugin.
However, it seems that new posts don't get automatically submitted to Flattr (are they supposed to?) - at least they're not showing in the Flattr Dashboard.
I guess this is the main reason why older posts (when i still had the original Flattr plugin installed) seem to work and newer ones don't.
The newer ones always have an orange exclamation mark for the Button - and yes, this is happening in Multisite.
If the plugin is not supposed to send the posts to Flattr automatically, maybe take this as a feature request ;)
Just to mention it, i've tried setting the language to an other language and back to English but it didn't help.