ERROR_INTERNET_NAME_NOT_RESOLVED

Hello everyone.

I'm trying to publish a ess portal on the internet.

I have a fully qualified name for the ESS portal and the backend R3 system (external names) .

Everything is working ok except the CSS is not loading .

I trace the webpage with httpwatch and  find out  that at some point i got the error "ERROR_INTERNET_NAME_NOT_RESOLVED" when i try to load a CSS file "http://<internal name>/com.sap.portal.design.urdesigndata/themes/portal/A_AJAX_theme/ls/ls_ie6.css?v=7.33.3.75.1 ".

Do you know what i need to change to correct this issue?

Best Regards,

Telmo