jambook version: 1.0 RC1

Initially it was working fine until it received a few spam entries.

My Spam setting is as follows:
Use CAPTCHA: yes
Spam Treatment: Don't publish
URL = Spam: yes
Image = Spam: yes
Only Smileys: yes

Posting settings:
Use Preview Page: yes
Allow Guest Names: yes
Posting Restriction: Public
Auto Approve: no
Edit Hours: 1
Flood Protection: 60
No Double Postings: yes
Strip HTML in conteht: Keep all HTML
WYSIWYG Editor: no

With these settings, when I do not enter Title and hit Preview button, I get a reminder message 'you need to enter title' and when I do not enter Entry I get a reminder message 'you need to enter something in entry'. But when I enter something in the Entry field and hit Preview, nothing happens and in the error console, it shows 'error: form.url is undefined'

Before it started doing this, the only thing I changed was 'URL = Spam: yes' but even if I change it back to 'URL = Spam: no' the same result.

What could I have wrong?

Any input on this?