1. Check if there's javascript in the page. if that's the case, forget mechanize. it might not work
2. if using IE, use win32::IEAutomation, might be easier to handle such pages
3. Instead of sleep(5) check the function for Win32::IEAutomation to wait for complete loading of the page
This will actually wait till the page loads if there is a lag..this works with IEautomation only..