Exception from "Run test": Error: Unable to find storage path mobile agent

Hi i have two devices connected for pagetest private instance . both two was working correctly
one devices is started giving below error for google nexusu 5 phone

Nov_27_11:54:24.498 C:\mobiletesthost\src\wpt_client.js:440 Client.processJobR
esponse_ : Got job: {“Test ID”:“151127_BF_1Y4”,“url”:“http://www.naukri.com/”
,“fvonly”:1,“Capture Video”:1,“runs”:1,“browser”:“Chrome”,“orientation”:“default
“}
I Nov_27_11:54:24.520 C:\mobiletesthost\src\agent_main.js:261 Agent.app_.schedul
e.addErrback.job.agentError : Starting run 1/1 of job 151127_BF_1Y4
E Nov_27_11:54:24.609 C:\mobiletesthost\src\process_utils.js:333 ChildProcess. : ./ipfw_config clear --device 07a4e5170222de96 failed with exception:
spawn ENOENT
I Nov_27_11:54:24.934 C:\mobiletesthost\src\browser_android_chrome.js:105 new Br
owserAndroidChrome : BrowserAndroidChrome({“cmd”:“run”,“runNumber”:1,“isCacheWar
m”:false,“exitWhenDone”:true,“timeout”:120000,“runTempDir”:“runtmp/07a4e5170222d
e96”,“flags”:{“captureDir”:“C:\mobiletesthost\\lib\capture”,“chromedriver”:”
C:\mobiletesthost\\lib\webdriver\chromedriver\Win32\chromedriver-2.4.exe”
,“maxtemp”:45,“name”:“motog”,“deviceSerial”:“07a4e5170222de96”,“location”:“LAN_W
PT_Mobile”,“browser”:“browser_android_chrome.BrowserAndroidChrome”,“serverUrl”:"
pagetest.####.com"},“task”:{“orientation”:“default”,“Capture Video”:1,“fvonly”:
1,“runs”:1,“Test ID”:“151127_BF_1Y4”,“url”:“
http://www.####.com/”,“browser”:“C
hrome”}})
.E Nov_27_11:54:26.839 C:\mobiletesthost\src\wd_server.js:197 WebDriverServer. : Exception from “Run test”: Error: Unable to find storage path
I Nov_27_11:54:26.842 C:\mobiletesthost\src\wd_server.js:1170 WebDriverServer.
: Test passed
I Nov_27_11:54:28.287 C:\mobiletesthost\src\wd_server.js:1190 unknown : Ignoring
screenshot error: Unable to find storage path
I Nov_27_11:54:30.791 C:\mobiletesthost\src\agent_main.js:141 Agent.
: wd_server child process exit code 0 signal null