Dear Damian,
the shown error message looks like the corresponding setup file (data2.cab) is broken.
From the displayed path I assume you are installing directly from the ARIS installation DVD, right?
If so, try to copy the setup folder "ARIS Platform" to your hard disk before runnign the setup. If the DVD is really broken, a read error should occur during that copy process, too. If not, try to run the setup from the copied folder.
If that leads again to that error message, please contact the Global ARIS Support at arissupport@softwareag.com.
Cheers
Rune