upload RAR & ZIP in code igniter

[eluser]loca[/eluser]
I've added the following code into mines file:

Code:

'rar'   =>  array('application/rar','application/x-rar','application/x-rar-compressed')

now, I can upload RAR files,

the following code is available in mines files by CI:

Code:

'zip'    =>  array('application/zip','application/x-zip', 'application/x-zip-compressed'),

but I can't upload ZIP.

Anybody there help me!!!!