I tried installing the application using iTunes (on Windows 7) to my iPhone 5, but could not reproduce the issue.
This seems to be an iPhone issue rather than application issue.
1. Can you please try out resetting your home screen
Settings > General > Reset > Reset Home Screen Layout.
2. Moreover there is a limit to the number of applications that can be installed on iphone at any time.
3. Can you please verify that your are seeing this issue with only PS Express app or any other application too?