This typically means that you need to configure your site to use v2.0 of the .NET framework. aspnet_regiis -i is one way, another is to manually switch to 2.0 in the ASP.NET tab of the sites IIS property window.
**Server Error in ‘/CatalogWebService’ Application.
Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.
Parser Error Message: File or assembly name Microsoft.CatalogServer, or one of its dependencies, was not found.
Source File: C:\WebSites\CSAdmin\CatalogWebService\web.config Line: 77