Problem - While installing Dynamics AX 2009 Reporting Extensions on SQL Server 2008, you might run into the following error - "You must install SQL Server 2005 Reporting Services Service Pack 2 before installing the reporting extensions". Look at the Screenshot below
1. Locate the AX Reporting services dll from the extracted AX 2009 SP1 folder [\\AX2009SP1\support\axsetupresources\microsoft.dynamics.setup.reportingservices.dll;File Version - 5.0.1000.52]
2. Copy the microsoft.dynamics.setup.reportingservices.dll into the folder: \\DynamicsAX\Msi\Components32\Program Files\Microsoft Dynamics AX\50\Setup [since my system is 32-bit so Components32]
3. It will ask to replace the existing dll having File Version - 5.0.593.0. Say Yes and replace. Now, carry on with the installation process.
Please read this post for further information and thanks to the poster for the steps - http://community.dynamics.com/forums/t/12322.aspx