TMG 121 The semaphore timeout period has expired.

Hi Experts,

i seem to be having a strange issue while trying to access the site www.octogen.co.za
The site opens but does not load fully, after about 15 - 20 minutes of waiting the site will eventually load.

If i check the TMG logs i noticed the follow
Allowed Connection TSRMGP001 2011/10/05 11:05:47 AM
Log type: Web Proxy (Forward)
Status: 121 The semaphore timeout period has expired.  
Rule: OMSTA WEB Access
Source: xxx.xxx.xxx.xxx
Destination: 196.7.147.227:80
Request: GET http://www.octogen.co.za/wp-content/themes/octogen/js/libs/modernizr-1.6.min.js 
Filter information:  
Protocol: http
User: domain\user

Even if i create an access rule from 'internal' to 'external' the same result occurs

I'm using ServicePack1 update 1

any assistance would be greatly appreciated

Thanks