Upgrading the Media Builder component fails on Windows Server 2003. The problem can be solved by installing a Microsoft hotfix
You attempt to upgrade from Acronis Backup & Recovery 10 to Acronis Backup 11.5/11.7;
During upgrading the Acronis Bootable Media Builder, you receive an error similar to:
File C:\WINDOWS\Installer\364afaa.msi was rejected by digital signature policy
Microsoft Windows Installer has insufficient memory to verify the .msi package.
Please apply a Microsoft Hotfix that you can download from the Microsoft knowledge base (http://support.microsoft.com/kb/925336).