Don’t know exactly where to begin.
First off, codec: This stands for Coder/Decoder, and refers to a program or device that can encode or decode a data stream or signal. Codecs are often necessary to view certain types of video files, such as Xvid or Divx, or the DVD format. There are many, many different types of codecs. Look up the definition at wikipedia if you want more information.
What are you using to watch the video on your computer? Which media player?
What software are you using to capture video, and what format are you using? Are you making avi files, mpeg2 files or what?
What software are you using to author your dvds? In other words, how are you putting them into dvd format? Did the Pinnacle card come with its own software package?
Give us a bit more info and we should be able to help. Speaking of help, you might also want to look through some of the capture guides at www.videohelp.com