Same problem, more depth here though.

I've got three characters running. I've created up to five before the glitch happened. It seemed to trigger when I hit level 30 on one of my mains. Stick with me here...

After I hit level 30 I booted up one of my others and gained a few levels, then did the same with yet another of my characters. The problem kicked in when I tried to make a new one. I've done this multiple times now. The problem isn't that XP doesn't go up, it does... the game simply lets it build up and never gives you the level up screen.

1. After my guy didn't level up after I had around 1200 xp (out of the 200 you need for level 2) I cleared the cache (deleting the patch) and rebooted that character. No change.

2. I deleted the guy and made a new one (no patch). Same problem.

3. Then I downloaded the patch again and tried reloading the last one I made. No Change.

4. Deleted last toon, made a new one (with patch). Same problem.

This is a pretty major bug to slip by QA checks and testing. And browsing many forums about this now I'm seeing that I'm far... FAR from the first person to have this problem.