Hi,
First of all you should use a folder like "i-doit", so that there is not a version in your URL. For the installation you do not have to use the "?load=update" at the end.
If you use an easy name for your folder, you should reach i-doit with an URL like http://localhost/i-doit and see the installation process.
Since you are using the open version of i-doit, our installation description in our Knowledge Base is not perfect but shows how to do it correctly. You can find it under https://i-doit.atlassian.net/wiki/display/KB/Installing+i-doit+pro
Kind Regards