Two state script monitor not working in SCOM 2012 R2 -

trying set simple two-state script monitor in scom 2012 r2 check existence of particular file on server. code follows:

$api = new-object -comobject ‘mom.scriptapi’  $bag = $api.createpropertybag()  $exists = test-path ‘c:\temp\testfile.txt’  if ($exists) {     $bag.addvalue(‘state,’yes’) } else {     $bag.addvalue(‘state’,’no’) }  $bag 

if create monitor , enable given server, registers , has initial healthy state. if result returned ‘yes’, state should change unhealthy. however, if create test file, monitor never changes state. it’s targeted windows 2008 r2 server, , set run on 5 minute interval. if manually execute commands in ps window on server, returns appropriate data. parameter i’m using results monitor :

property[@name=’state’] equals yes (unhealthy) or                             no (healthy) 

i know i’m missing dumb..there’s not monitor. ideas?

tia.

try specify datatype in condition detection, like

          <expression>             <simpleexpression>               <valueexpression>                 <xpathquery type="string">property[@name="state"]</xpathquery>               </valueexpression>               <operator>equal</operator>               <valueexpression>                 <value type="string">yes</value>               </valueexpression>             </simpleexpression>           </expression>