An executable file has permissions
-rwxrwxr-x and owner is root. When a non-root user tries to execute the file, I get a permission denied error. What am I not understanding?
Where is the location of the file? Is the file in a readable directory?
EDIT: As well what does the file do? Inside does it execute something else that could have a permission issue?
Check the filesystem isn't mounted with the
noexec option, which will override the permissions on the file. Can root execute the file?
In order to execute you must also be able to read (except for root, who can do anything on plain unix systems)
If it is a script (i.e. uses
#! on the first line to tell the OS how to run it) check the permissions of the interpreter named there.