Visual Confirmation Problems

When someone goes to register on my site, it won't let them. It says this:
The number of entries of Visual Confirmation has exceeded the limit in this session.
How can I clear this or whatever it is I need to do? I have another problem with IPs but I'll address that after I get this issue fixed.
The number of entries of Visual Confirmation has exceeded the limit in this session.
How can I clear this or whatever it is I need to do? I have another problem with IPs but I'll address that after I get this issue fixed.