Every time I log back in, my autosipper is switched off again, and all the settings are back to the default. Is there something I've not done to make it stay on all the time?
Doesn't help you at all with your actual issue with the script, but there's built in server-side curing now, which includes sipping health and eating irid moss/potash. HELP CURING SYSTEM has all the details, but this should get it set up:
CURING ON to turn it on.
CURING TRANSMUTATION ON (if you use alchemical mineral cures) or OFF (if you use Concoctions plant cures)
CURING SIPHEALTH <percent> to set the percentage of your maximum health you want to sip health at (you probably want 80-85).
CURING MOSSHEALTH <percent> to set the percentage of your maximum health you want to use irid moss or potash at.
Can do the same thing for SIPMANA and MOSSMANA.
Answers
You certainly forgot to click on "Save Client Settings" on upper right.
The autosipper is turned on in-game, though. I haven't changed anything on the settings page, and the autosipper remains ticked whenever I log in or out. Everytime I log in, i have to AUTOSIPPER ON, AUTOSIPPER THRESHOLD etc.