jQuery Image Upload - JSON error

[eluser]Unknown[/eluser]
I need a help, I use jQuery Image upload like this

Code:

http://blueimp.github.com/jQuery-File-Upload/

I get the thumbnail and after clicking the upload button I get the progress bar, but then get 'SyntaxError: JSON.parse: unexpected character'.

In attachment is view and controller page

[eluser]Bhashkar Yadav[/eluser]
check JSON data string if it has square bracket at start and end. check by removing it.