Hello. I try instal iTunes 10.5.0.142. Wehn I try I see this ,, There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Concat your support personnel or package vendor." What I have to do ?

Hi

You will need to uninstall all traces of previous iTunes installations any all associated items such as bonjour, mobile device thingy, apple software updated etc.

Bonjour and iTunes can be uninstalled using the windows program uninstalled but for everything else best to use a separate installer program that also checks the registry for associated components as you will need to remove these too.

Once you have removed all tracesofeverything apple related ( doesn't seem to matter about QuickTime) you can try to reinstall iTunes 10.5 and hopefully it should install without any problems. I had the same problem as you and once I did all this every went through fine, seems that there is something in the old versions, the software updated part I think which seems to be blocking certain items in the latest version.

Good luck