That's part of the ahem-*charm....* of old school EQ.
Some common mistakes are:
misspellings
incorrect plurality
missing spaces
punctuation
Sometimes ''I will deliver the fishsticks'' doesn't work where ''I will deliver fishsticks'' does.
'The' seems to make it not work.
If all else fails, I take the easy way out and see if i can find the quest on the old Allakhazam site.
This site isn't updated anymore, but thats OK. look for the Bestiary by zone (alla) link under the drop-down resources bar on the right. Then search for the zone and NPC you're talking to. there should be some info there.
good luck!