I have a script that executes a file in a couple of directories down which looks like this:
exec(\"php-cli $file_path > /dev/null 2>/dev/null &\"); //p
Simple question perhaps, but does php-cli exist on all the hosts? I assume the reason its failing silently is because you're telling it to be redirecting everything away.
php-cli
exec("php $file_path > /some/writable/path/output.log 2>/some/writable/path/error.log &");