404 error – can't save feed

Hi

When I try to create a feed and then save it I get the following error:
Home→Blog→404 Page not found
Sorry, no such page.

The URL generated is:
http://www.ukhypnosis.com/wp-admin/admin.php?page=gf_constantcontact&view=edit&id=0

Any solution to this?

I have the following plugins installed
Aksimet
Jetpack
All in one favicon
Anti-malware
Better WP Security
Broken Link Checker
CRON Gui
Fast Secure Contact Form
Gravity Forms
Gravity Forms CC plugin
Growmap AntiSpam Bot
iDrive
RSS Importer
Subcribe 2
Sucuri Security
Theme Authenticity Checker
Use Google Libraries
Wordpress RSS Shortcode
Wordpress SEO
WP Table Reloaded
WP Super Cache
WP Zopim Widget

Thanks
Mark

http://wordpress.org/extend/plugins/gravity-forms-constant-contact/