QII 10.1 sp1 free installation problem

I'm using windows 7 and get an error while decripting the QuartusII installation file.

The error is:

CRC failed in 10.1sp1_quartus_free_windows\devices\subscription\arriaii.qda

after the CRC error the insallation fails.

This does not happen on every computer but on only on some of them.

Is there any known issue regarding firewall, antivirus, windows 7 professional or home edition that I need to know in order to solve the problem?

Thanks in adavance for any hint.