Can't really say that different codecs cause me many problems

Go to http://www.afreecodec.com/

and download afreeCodecVT. It's a window that you drag your moviefile to and it identifies the exact coded being used both video and audio. The same page also has many other helpful downloads.

Also at http://www.digital-digest.com

you will find alot of helpfull stuff

+ Nero is always trying to include more and more codecs for their software, so even if your current version won't support it, just go and see if they don't have a update ready for you

That of course implies that you bought and paid for your Nero
It is one of the few programs out there that is actually worth the money they (undercharge) for it