As an advanced user you should know that gknot and klite are codec PACKS (and if you read BSPeter post you surely saw the lines where he tell to NOT use codec packs).
Furter also if you have read the BSPeter post, and as I suggested you, you should have found also lines where GSpot were named. It's an utility to know which one codec was used to compress the video file -> using it will let you know which codec do you need to install onto your computer.
I used gordian knot codec pack for a long time, it's really soft and clean, if you want you can use it (except for the DivX 5 codec, since I had problems with the one included in such a package, so download DivX 5 or 6 from other sites).
If after using GSpot you find that a needed codec is not installed on your pc, then post again a message by saying which codec do you need..
