A plug-in is an xtra mini program that the main program may call upon if needed. In this case we're refering to
CODECs.
Why not skip the DivX & instead do your converting using Nero. Someone mentioned to me that Nero is unable to burn DivX due to it being a copyright format. (However there may be a divx burner I don't know!)
I only have Nero 5 so my very limited knowledge is somewhat reached. The image below shows Nero burning rom & Nero Express. I was able to drag & drop an avi file to both. Nero does the conversion. (But that's for VCD!)