I really am only posting this so I don't forget again.  2003 doesn't have solutions and features so I couldn't remember how to deploy the SPS 2003 web part code I'd fixed.

If you have a CAB file and need to deploy it, use the STSADM AddWpPack command.  I'd detail everything for you, but this guy already did it for me back in 2004.  His post is excellent, well written, and includes better screenshots than I would create.  I'm just going to link to his work...