During the installation of Vault Professional 2012 (Server) you can sometimes get this error
Error 29001. Vault Management error: IIS 7.0 Detailed Error - 500.19 - Internal Server Error.
To address this issue....
Browse to the IIS configuration files located in "C:\Windows\System32\inetsrv\config\applicationHost.config"
Open the file applicationHost.config file in Notepad and modify the line <section name="requestFiltering" overrideModeDefault="Deny" />
Save the file and close Notepad.