It must be Windows 7 Professional 64 bit. Do you have that, or something else?

(There was some weird stuff going on for me with 32-bit Windows 7 Professional with TIA Portal V13 (because it uses different, less tested code), and ultimately was a waste of time instead of just buying Windows 7 x64 Prof)

Try to look at the "Properties" of the setup.exe on the dvd.

See if the "Compatibility" is enabled. If it is, then disable it and try again.