VS 2013 debuging webSite hangs but not IIS

Hi everyone

This is my first post here. I'm very new to the technology, so some question my seam strange.

I'm trying to debug a website(maded by someone that i never knew, at the company). And  when i go debug, visualStudio launch a browser withhttp://localhost:49196/  and there, some components don't work properly. Most of the components are made with devExpress.
i checked the debug on the browser and i got errors like  " ReferenceError: WebForm_InitCallback is not defined", and syntax on js.

but if i launch the aplication on iis manager, i go to http://localhost/ and there, everything works fine!

Does anyone know what i'm doing wrong?

Thanks