i came across this hope it helps`
Error "...failed to start because ad2mpegin.dll was not found..." when you start an application after installing Premiere Elements 2.0
When you start various third-party audio or video applications, the applications return the error message, "This application has failed to start because ad2mpegin.dll was not found. Re-installing the application may fix this problem."
You are running Windows Media Center and recently installed the Windows XP Media Center Rollup 2 update.
You recently installed Premiere Elements 2.0.
Do one or more of the following solutions:
Solution 1: Add the ad2mpegin.dll and ad2mcmpgdec.dll files to your Windows\System32 directory.
This error message appears because the application you are attempting to start cannot find the ad2mpegin.dll file on your system. If you see this error message when you start an application, and you recently installed Premiere Elements 2.0, copy both the ad2mpegin.dll and ad2mcmpgdec.dll files from the Premiere Elements directory to your Windows\System32 directory:
1. Navigate to the Premiere Elements 2.0 folder. By default, this folder is installed at C:\Program Files\Adobe\Adobe Premiere Elements 2.0.
2. Copy the ad2mpegin.dll and ad2mcmpgdec.dll files.
3. Navigate to the Windows System32 folder. By default, this folder is installed at C:\WINDOWS\system32.
4. Paste the ad2mpegin.dll and ad2mcmpgdec.dll files into this folder.
Note: You may also need to copy the ad2mpegin.dll and ad2mcmpgdec.dll files to Windows\ehome and to the program folder of the application that you are trying to start.
Solution 2: Restore your system to an earlier state.
This problem stems from changes made to the system that were implemented in the Windows XP Media Center Rollup 2. Restore your system to a state prior to the installation of this Windows update.
The files ad2mpegin.dll and ad2mcmpgdec.dll are codecs installed by Premiere Elements 2.0. Some third-party applications are designed to load all codecs that are installed on the system when they start. These applications detect when ad2mpegin.dll and ad2mcmpgdec.dll are installed, but they are unable to locate these files in the Premiere Elements 2.0 folder.
This error may appear when you start Windows Media Center, Spotlight, or when you start your system.