Hi Vincenzo,
I have no experience of HCP server,as far as I know,there are two ways to develop UI5 application:Local Eclipse or Online RDE.If you are developing apps in Eclipse, you must assure that the UI5 develop add-on(UI Development Toolkit for HTML5) is installed correctly so that you can take use of the local UI5 core library resource,the following link may help you:Download Evaluation Package for UI Development Toolkit for HTML5 ;If you are using RDE, please refer to http://scn.sap.com/docs/DOC-55466 .
Regards,
Seaman