FileUploader is not working in gridview inside Updatepanel

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C#

Hi all,
I have gridview inside the updatepanel...In this gridview i have image inserting and updating process in imagebutton...

For this inserting and updating i have used fileuploader in C#...When clicking insert button it fires the fileuploader event...

When it fires fileuploader it shows error as "Object reference not set to an instance"....Because the fileuploader event is inside the updatepanel....

When the fileuploader event outside the updatepanel it works fine...But fileuploader with updatepanel is important for my project....

So please help me to solve this problem....

Regards
vivekx2