Hi Rekha,
I downloaded the sample you provided and watched the video and they both seems to show the tiles working fine.
I tried excluding all of my other javascript libraries like devexpress and few others, but I still got the same problem.
For test/debug purposes I have uploaded a tile test page to my production website so you can check it on your end.
The link is http://tinyurl.com/zbjno8x. Can you try it and see if you can find out what is going on.
Many Thanks,
Ardani