If they're fields on the hero, then you need to tell Hero Lab that it's looking for a field on the hero:
Code:
doneif (herofield[acHPNow].value <= herofield[acHPBlood])
Remember, capitalization matters - acHPNow, not ACHPNow.
Also, both of those values aren't calculated until Final/9000, so your script, running at Initialize/1000 will always see the value of both as 0, so it will always exit the script.