Why I have to install pimcore into the document-root?
Pimcore isn't designed to operate on shared hosts, so we don't care about the needs for those systems.
On dedicated systems you can create as much virtual hosts as you like and the install into the document-root shouldn't be the big deal.
Why pimcore doesn't work on my webspace?
Well, pimcore has special needs to the running environment. Most of the webhosters don't offer or limit them.
Please read more about the minimal system-requirements here.
We highly recommend to run pimcore only on dedicated systems (root-server, ...).