Interact with external commands via shell_exec

Interact with external commands via shell_exec

Recently I installed Android SDK on my CentOS server because of working
with aapt, the aapt works great in command line via Putty SSH application.
Now, I want to run aapt commands through php shell_exec method.
My Android-SDK has been installed on \ipl\android-sdk\platform-tools\aapt,
but I can't interact with it through shell_exec method, my code:
Code:
$out = shell_exec("/ipl/android-sdk/platform-tools/aapt d badging t.apk
2>&1");
var_dump($out);
Result:
string(60) "sh: /ipl/android-sdk/platform-tools/aapt: Permission denied "
Any ideas?