When I first downloaded and used InstallShield 2011, I noticed that when you try to sign a release in the Releases view, it will fail. This applies to Basic MSI, InstallScript MSI, and InstallScript projects.
This has since been resolved, so I thought I would point out a Knowledge Base article to you. Here is the link:
The hotfix has an attached zip file with a new version of IsWsBuild.ocx. Unzip the file and place it in the following folder: