MS CRM 2011 on premise.
No problems if accessed via internal address: crm:5555
Go to crm.ourcompany.co.uk:5555 in IE and load account page and the ribbon is totally grey. (Not disabled - every pixel is the colour grey.) 
In Chrome and Firefox the ribbon is loaded fine.
Browser console in IE, Chrome and FF all say access errors.
I can see they are trying to access crm:5555.
IE says:
SCRIPT5:Accessis denied. PageLoader.js, line 1 character 1226
The second line above is presented as a link. Clicking it shows me this: http://pastebin.com/bBadk9HS
The full path is http://crm.ourcompany.co.uk:5555/_static/_common/scripts/PageLoader.js?ver=-1056260279
P.S. IE is "Browser Mode: IE10 Document Mode: IE9 standards".
P.P.S. I'd prefer it if you answer at http://stackoverflow.com/questions/17545918/grey-ribbon-on-account-form-in-ie-script5-access-is-denied-in-pageloader-js