Like AlexT Said Make sure you have downloaded the 7.0.4 to 7.0.5 upgrade Patch and removed the .htaccess file from /public_html/upgrade or /public_html/dolphin*/upgrade. Then goto http://mysite.com/upgrade. If you've just uploaded 7.0.5 Then you may have to start again. you could try re-uploading 7.0.4 and hope that it will not break your site but this isn't a smart move and i'm sure Boonex would say it's better to do a clean installation.

* Replace dolphin with your dir (eg. site)