You might encounter this issue when installing Plesk 11 with Microsoft SQL Server on Windows :
Unable to install the “mssql2008_configurator-1.0.noarch” package. The following could cause the installation failure: 1) mssql2008_configurator-1.0.noarch: No suitable solutions were found for the “msi45 >= 4.5.0000.0000” dependency. 2) The dependency for “msi45 >= 4.5.0000.0000” required by the “mssql2008_configurator-1.0.noarch” package could not be resolved.
This is because the Windows Installer 4.5 [KB942288] component is missing for MSSQL installation.
Manually download/install and reboot, then restart the Plesk installation.