That is not much help. What feed are you using and where are you entering it? The exact error message would also help.
please clear your question more.. the information you have provided us is not enough to solve this issue..
when i go into syndication, i got to change feed, i enter the different feed, then press (use this feed) and it turns out empty and says, no feed selected, i tried this with different feeds and same thing, dont know.