Magento

I’m using linux mint, linux kernel 2.6.22-14-generic with disabled firewall. I use Magento Magento ver. 1.0.19870. To try out Magento, I installed two copy of Magento. One with secure admin backend and the other with plain http backend.
I have problem in uploading Images in the Product Information panel in secure admin backend. When I clicked the Upload Files, the button didn’t do anything.
I don’t have the problem with plain http backend, I can upload images successfully. Please help. Thank you.