The lights being on while flashing is a good sign!
Check, whether I renamed the files for flashing right (no typo\'s), that the files have the correct size etc, that the cf-card is suitable for flashing and that the Zaurus is plugged in.
Then try flashing several times. It took me sometimes 3 times with the same setting on the SL-5500.
Don\'t give up.
Good luck,
Kathrin