[Checkout] Unable to activate

Hello, I'd piggy backed on a previous thread about the same problem so thought it cleaner to start one for my own particular issue

I'm unable to activate the Checkout Module, I can configure it, and I have the checkoutpaypal module also loaded but the Checkout module has no activation link.

Any idea why this might be?

I have tried removing Cart, Checkout & Checkout Paypal and then re-installing Checkout & Checkout Paypal but this does not resolve the issue. I have tried installing either a seperately downloaded version of checkout and also the 'get plugins' method too.

CheckoutPricing & CheckoutProducts have been added as common fields in the custom field section
Is it a case of some of the fields being required prior to the activation link becoming available? If so, which fields?

Details of the configuration follow...

Site: http://www.shutter-life.co.uk/gallery/

Gallery version : 2.2.4
Module / Theme name & version: Checkout 0.0.18 on PGLightbox Theme 1.2.0
PHP version : 4.4.4
PHPInfo Link (see FAQ):
Webserver : Apache 3
Database : Mysql 4.1.22
Activated toolkits : GD
Operating system : Linux
Browser : IE 7 & Firefox

Thanks,
Rob