Nis 18.5 Blank DVD insertion

Hi everyone,
I have NIS 18.5 italian installed on 3 pc: a desktop with win7 32 bit, a notebook with win7 32bit and a notebook with Vista 32 bit SP1
After 18.5 on the 3 pc when I insert a blank dvd the system try to loading to infinity the dvd and the dvd is not avaible to use in the pc. There are no error both on windows or NIS event manager but I found that if I put NIS in silent mode the problem disapperar.
Waiting for a reply, thanks in advance.

PS: on the 2 notebook NIS was updated from 18.1. In desktop was a clean installation because I buyed the pc this month.