You host does not allow chmod or will not chmod files for you? I have never heard of that.
I know of some Microsoft hosts they would need to make the appropriate changes but on a linux account you can always chmod files you own.
Basically file permissions are this
666 is read and write
777 is read write execute
so if you have some sort of ability to set some type of permissions based on this you should be okay.
The program would normally be installed in the public folder if you want it viewable to the web
