Unable to launch application


This is my first experience with VPS. I am trying to run a cgi Web Real Studio app, but when I try to connect to the web site I got the error message: "Unable to launch application ‘name of the app’ on port xxxx’
It seems to me that there is something related with denied permissions somewhere, but I am really stuck with this.
I uploaded the app and its libs folder in binary mode, everything else in ASCII mode.
I have modified permissions of files (755): config, app, cgi, …
Any help will be appreciated.