These previous discussions may help... or may not, I don't do screen capture video
Techsmith codec http://forums.adobe.com/message/3692768
is there no way to add new codecs to premier?
If you are using the software the codec is already on your machine, but Premiere does not reconize it.
If i am not mistaken you can set capture/export codec to Lagarith in Camstudio.
Premiere has no problem with Lagarith.
If you still want to use the file you have just made then you will have to convert first.