Error: write failed: EPIPE (Broken pipe) about roottools HOT 8 CLOSED

Here after a detailled log:
05-03 17:38:06.109: D/RootTools v1.7(1755): Checking for su
05-03 17:38:06.109: D/RootTools v1.7(1755): Trying second method
05-03 17:38:06.109: D/RootTools v1.7(1755): Checking for su
05-03 17:38:06.109: D/RootTools v1.7(1755): su was NOT found here: /sbin/
05-03 17:38:06.109: D/RootTools v1.7(1755): su was NOT found here: /system/bin/
05-03 17:38:06.109: D/RootTools v1.7(1755): su was found here: /system/xbin/
05-03 17:38:06.109: D/RootTools v1.7(1755): su was NOT found here: 
/data/local/xbin/
05-03 17:38:06.109: D/RootTools v1.7(1755): su was NOT found here: 
/data/local/bin/
05-03 17:38:06.109: D/RootTools v1.7(1755): su was NOT found here: /data/local/
05-03 17:38:06.109: I/UiRecorderActivity(1755): SU is available !
05-03 17:38:06.109: D/RootTools v1.7(1755): Sending 1 shell command
05-03 17:38:06.129: W/System.err(1755): java.util.concurrent.TimeoutException
05-03 17:38:06.129: W/System.err(1755):     at 
com.stericson.RootTools.Executer.sendShell(Executer.java:95)
05-03 17:38:06.129: W/System.err(1755):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1112)
05-03 17:38:06.129: W/System.err(1755):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1079)
05-03 17:38:06.129: W/System.err(1755):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1171)
05-03 17:38:06.129: W/System.err(1755):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1197)
[...]
05-03 17:38:06.129: W/System.err(1755):     at 
android.view.View.performClick(View.java:3511)
05-03 17:38:06.129: W/System.err(1755):     at 
android.view.View$PerformClick.run(View.java:14105)
05-03 17:38:06.129: W/System.err(1755):     at 
android.os.Handler.handleCallback(Handler.java:605)
05-03 17:38:06.129: W/System.err(1755):     at 
android.os.Handler.dispatchMessage(Handler.java:92)
05-03 17:38:06.129: W/System.err(1755):     at 
android.os.Looper.loop(Looper.java:137)
05-03 17:38:06.129: W/System.err(1755):     at 
android.app.ActivityThread.main(ActivityThread.java:4424)
05-03 17:38:06.129: W/System.err(1755):     at 
java.lang.reflect.Method.invokeNative(Native Method)
05-03 17:38:06.129: W/System.err(1755):     at 
java.lang.reflect.Method.invoke(Method.java:511)
05-03 17:38:06.129: W/System.err(1755):     at 
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-03 17:38:06.129: W/System.err(1755):     at 
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-03 17:38:06.129: W/System.err(1755):     at 
dalvik.system.NativeStart.main(Native Method)
05-03 17:38:06.139: D/dalvikvm(1755): GC_EXPLICIT freed 81K, 10% free 
9272K/10243K, paused 1ms+1ms
05-03 17:38:06.149: D/RootTools v1.7(1755): Using Root
05-03 17:38:06.149: D/RootTools v1.7(1755): Shell command: setprop my.key start
05-03 17:38:06.149: D/RootTools v1.7(1755): Error: write failed: EPIPE (Broken 
pipe)
05-03 17:38:06.149: D/RootTools v1.7(1755): In finally block
05-03 17:38:06.149: D/RootTools v1.7(1755): Getting Exit
05-03 17:38:06.149: D/RootTools v1.7(1755): Exit done...

I don't think this is an error with RootTools but with setprop. Does this same 
command work if executed from the shell on your phone?

[deleted comment]

With Android Terminal Emulator you mean ?
I am trying ...

SO the result:
a getprop works.

But for setprop i need su, but when I try su:

app_66@android:/ $ su
su: uid 10066 not allowed to su

:/

Ok I tried again now I have:
[...]
05-04 09:33:51.587: D/RootTools v1.7(3834): su was found here: /system/xbin/
[...]
05-04 09:33:51.587: D/RootTools v1.7(3834): Sending 1 shell command
05-04 09:33:51.597: W/System.err(3834): java.util.concurrent.TimeoutException
05-04 09:33:51.597: W/System.err(3834):     at 
com.stericson.RootTools.Executer.sendShell(Executer.java:95)
05-04 09:33:51.597: W/System.err(3834):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1112)
05-04 09:33:51.597: W/System.err(3834):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1079)
05-04 09:33:51.597: W/System.err(3834):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1171)
05-04 09:33:51.597: W/System.err(3834):     at 
com.stericson.RootTools.RootTools.sendShell(RootTools.java:1197)
[...]
05-04 09:33:51.627: D/RootTools v1.7(3834): Using Root
05-04 09:33:51.627: D/RootTools v1.7(3834): Shell command: setprop my.key 1
05-04 09:33:51.627: D/RootTools v1.7(3834): Done reading input stream
05-04 09:33:51.627: D/RootTools v1.7(3834): error stream: su: uid 10065 not 
allowed to su

Strange, how a "su" binary cannot provide access to it ?

I'm not sure what is happening there, however I am pretty certain that what is 
happening is not related to the RootTools library :\

I have the same EPIPE broken issue on rooted android 4.0.3 devices with and 
without RootTools. So the issue shall not be related to RootTools. The problem 
is almost all the devices I tested broke the same way.

To test without RootTools, use this basic code:

Process su = Runtime.getRuntime().exec("/system/xbin/su"); // my is here

DataOutputStream os = new DataOutputStream(
su.getOutputStream());

// Getting the id of the current user to check if this is root
os.writeBytes("id\n"); // IOException EPIPE broken thrown there.
os.flush();

Off course, this is the correct path and name. I also tried many different su 
supposed to be OK but failed the same way.