The problem with the above code is property values are not passed to server side at the time of modify the features. By setting the Secure attribute to 'yes' in property element it is working fine.By default Secure='no' in property element.
<Property Id="WORD14_32" Secure="yes">
<RegistrySearch Id="Word14_32"
Root="HKLM"
Key="SOFTWARE\Microsoft\Office\14.0\Word\InstallRoot"
Name="Path"
Type="raw"/>
</Property>