Ran out of startup disk space on 10.4.8 update, now KP at startup

[GrumpyOldMan]

I'd try this:

Connect to your messed-up Macbook via FireWire target mode. Can you do a "repair disk" on the FW-mounted Macbook disk from the host computer? If so,do that.

If I were you, I'd do this:
1) buy another external disk (maybe 250 GB ) and an external FW/USB2.0 enclosure.
2) copy all your useful data to that (use ditto from the command line or CCC); don't copy system files since they're probably messed up from partial upgrading.
3) when done, reformat your Macbook disk and get rid of that stupid partiioning; I don't know what you were thinking when you did that.
4) Reinstall 10.4 on the MacBook, run all updates
5) Reinstall all your 3rd-party apps, install all updates
6) copy back your files from 2) to your Macbook.
7) When satisfiied that everything is OK, reformat your new external FW disk and set up a reasonable backup solution (Retrospect or BRU) and backup your MacBook every night while you sleep.

And NEVER let your disk get that low on space again! UNIX needs room to work (your swap space can easily be several GB when doing actual work).