I found out the problem. We are creating 2 different canvas and renderer which will show the scene on the browser and another canvas will create scene for taking screen shot for PDF generation. I was assigning one renderer to another, when i commented this the error is gone now. i feel both renderer where active and assigning one to another is causing some corrupt in renderer.
Also using texture as variable name could also cause this. i just read in other blog but did not see any difference for my case.
Anyways thanks for your reply and advise.