Hi Guys , I changed the media folder permission 777 ,
drwxrwxrwx 4 geetha geetha 4096 Jun 25 15:16 media.
I updated browser not help.
I installed Flash player not help.
I flushed the magento cash not help.
In the System.log not showing any error.
One more thing i have to mention is that , we have three systems running Uubuntu 12.04 , its happening in only one system. in other two we dont have any problem.
please tell me What could be the problem?