web aplications don't run after installation

[ajerez]

I made a new installation and after that I don't have access to the applications that where running under my apache webserver (I have a wiki and a dotPrtoject installation), I obtain a a message saying object not fund when I try to access them via for example http://localhost/...
The apache daemons are running right.

Is there anything else that I have to do after Plesk installation ?

Thanks in advance.