When you click the HUD, or when you select the HUD menu, nothing happens. For example,

• you click "re-setup" and start re-setup, but there is no setup ball.
• you click a toy button to rez a toy, but nothing happens.
• you click "transfer..." to transfer your settings, but nothing happens.
• when you are in the middle of a setup, and the ball stalls and you can't continue.
• ... etc.

That may mean that SL memory issues have caused a stack heap collision error (or some other similar script run-time error) on one or more scripts on your HUD.

To fix, do a Smart Reset. (If you are using HUD v4.12.x, you might need to smart reset a few times.)

If that doesn't work, you might consider starting over by getting a fresh set from the Update Switch at the Secret Warehouse.