I created the render preset in my machine, it automatically creates the mel files in C:\Documents and Settings\narasimham.k\My Documents\Maya2010\2010-x64\presets. I copied those files in D:/ and change the path in Maya.env as MAYA_PRESET_PATH=share location.
After opeining the maya I am getting the MAYA_PRESET_PATH as 'share location' through getenv, but I am not getting the copied rendered presets.
I don't think MAYA_PRESET_PATH helps with render presets:
http://mayafail.blogspot.com/2010/02/mayapresetpath-is-abortion-of-shame.html