WordPress Theme Installation Failure

I purchased a new wordpress theme and when I try to upload it and the upload reaches 100% the webpage fails as if it has lost its connection. When I refresh the page I get a blank, white page that says “are you sure you want to do this” and no option to click. Shortly after that page and any page I have open to do with my hosting account or with wordpress fails and requests to be shut down.

I have installed a wordpress theme before and never experienced this problem.

Please help – i’m totally frustrated.