I keep getting characters and words I got right over and over again. Also, even if I skip the characters, it comes back eventually and doesn't count as a "learned" word. Please help ASAP. Thank you.

If the words comes back up and you know them then its good for you to just review them once more......
But I don't know if that is a problem or not..

Is the iOS or web version? Also, do you have enough new words to add–is your problem solved if you manually add new ones?

If it were the web version, I would suspect connectivity problems. Possible?

I started to have similar problems about 12 days ago (and already submitted a bug report) for the web version. A couple of days ago I decided to use my iPod to continue. All worked fine for two or three days but somehow the synchronization didn't work: the web interface said I had 1200 reviews due, on the iPod I had 800 reviews do. Multiple "force syncs" didn't help. This morning I had 1400 reviews on the iPod (with about 20 items added yesterday) which I brought down to about 1000 after lunch. Now, at 4pm local time I have 1320 items due and see already learned word parts coming up again.

Connectivity problems are definitely possible since I'm in China. But I had this problems both with skritter.cn and skritter.com.