If you have both MOSS 2007 ( Microsoft Office SharePoint Server) and Reporting Services ( not in SharePoint integrated mode) installed on the same IIS virtual server, then you have to make the below updates in web.config for them to work

1)      In the Root web.config to comment out the below. Otherwise the reportserver will give sessionState partitionResolver Issue
<!-- <sessionState mode="SQLServer" timeout="60" allowCustomSqlDatabase="true" partitionResolverType="Microsoft.Office.Server.Administration.SqlSessionStateResolver, Microsoft.Office.Server, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
-->
 
2)      In both Reportserver  and ReportManager vdir web.config, the following should be added under appSettings. Otherwise you will get ReportViewer error messages
<remove key="ReportViewerMessages" />


This is because , by default MOSS uses /reports url for it’s report center and it’s the same virtual dir url for native SQL Reporting Services report manager as well.