Generally, there are 2 causes to a missing DLL:

 1. The MediaMonkey installation files were corrupted or the files were 

    corrupted subsequent to installation.  In this case, simply proceed

    with a clean install:

    http://www.mediamonkey.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=54

 2. Another application has interfaced with the Windows audio/video 

    subsystems and but has not copied files to the location that Windows 

    expects them to be in.  An example of this is an 'Active Movie' error 

    when trying to rip a CD that throws an error "This application has failed to

    start because ad2mpegin.dll was not found. Re-installing the application

    may fix this problem". This particular error can be caused by Adobe 

    Premiere failing to copy ad2mpegin.dll and ad2mcmpgdec.dll to the 

    WindowsSystem32 folder.

    In such cases, just copy the missing file(s) to the correct location.