Are you sure your entering the server path name correcty. Run test php file to get the server address, or ask your server for your path if your not sure. Because if the boards working fine, I really can't see why vbindex isn't also.
Other portals like vBadvanced CMS will get the path for you itself itself if I remember righ during the installation and tell you what to enter. Plus there is good suport for it unlike this product now which is an old one.
You better of using that instead of vBindex RC5, which you can download from here:
http://www.vbadvanced.com/products.php?