Why my tap utility does not work correctly

[AC Question]

I executed the command tlinput tap 240 700, and it gave me such a mistake:

===
java.lang.SecurityException: Injecting to another application requires INJECT_EVENTS permission
at android.os.Parcel.readException(Parcel.java:1472)
at android.os.Parcel.readException(Parcel.java:1426)
at android.hardware.input.IInputManager$Stub$Proxy.injectInputEvent(IInputManager.java:356)
at android.hardware.input.InputManager.injectInputEvent(InputManager.java:642)
at com.android.commands.input.Input.injectMotionEvent(Input.java:259)
at com.android.commands.input.Input.sendTap(Input.java:197)
at com.android.commands.input.Input.run(Input.java:104)
at com.android.commands.input.Input.main(Input.java:59)
at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)
at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:243)
at dalvik.system.NativeStart.main(Native Method)
===
Then I enter the command input tap 100 200, and it works great, as I defined this command, I only work within the terminal in which it is running!
I have a root on my phone right, but when I enter the console su and then input tap 100 200 then nothing happens and it's very strange.

 

[B. Diddy]

Moved to the Software Development forum.