Run freePBX in web folder

Does anyone knows that FreePBX can be installed on a Linux webfolder?

I have a web hosting service where I have a webfolder in the environment of Linnux and I was told that that that Linux OS will support software requires CentOS5.x

I extracted FreePBX 2.6.0RC2 into my local computer drive. Then, I FTP all files into my web folder in Linux environemnt. I use a web sub-domain to point to that web fold for the FreePBX2.6.RC2. I typed in the sub-domain address from a web brower and I got an error message: “Error 403 - Forbidden You tried to access a document for which you don’t have privileges.”

What I did wrong?
How can I use my Linux environment to run a freePBX so I do not have to have a server in my office?