An error occurred while installing OS X

When I tried to upgrade a old Mac Pro from 10.6.x (Snow Leopard) to 10.7.x(Lion) I got this error:

First I thought my Time or Date on the Mac where wrong – but no it was correct.

I tried to install from a disk-image (DMG) the solution where to drag (copy) the installer to

e.g. the Applications folder and then re-run the installer.