ADSI, or Active Directory Services Interfaces, is, an interface that allows different types of directory structures to be accessed by a single interface. It is needed in order for Server Control to function properly. Because it is a Microsoft program, please visit their site for more information about it and to download the most recent one for Windows NT for free.
Because the plug-ins may be manipulating data in different NT environments (IIS, LDAP, etc.), ADSI must be installed on both the PRISM server and the remote servers for these plug-ins to function properly.
For more information about ADSI, visit Microsoft’s site at http://www.microsoft.com