I now have exactly the same problem. I live and work in Italy. New website was launched 7 months ago - Twitter only just activated and started trying to use it yesterday to post tweets. Tried several simple hashtag tweets - all came up in subsequent search.
Then tried various test tweets with url.
1. Twitter automatic shortener did not appear - forced to use bitly.
2. Tweets with various website url's from our site not indexed.
3. BUT - urls from UK based sites fully indexed.(these were just used for testing)
4. Some US .com url's worked and were indexed. since all deleted.
5.This morning no url tweets indexed at all.
6. Is there a problem that we have a website in Italy that is 'set up' in English?
7. Have tried changing all settings to reflect Italy etc etc but still not working.
Anyone any suggestions? Any previous posters now had any joy?
Without url's in some tweets - our Twitter account is useless.
Have now deleted all tweets until matter resolved.