I was wondering about something.

I read in the hint guide that after you give Mekadawa the toad potion given to you as a cleric guild quest, you are supposed to be rewarded.

When I give the toad guy the potion he says "I need this, Toad need this" I then go back to the Cleric and it is like Nothing happend. In fact he asks me to do it again.

Am I doing something wrong?

To get the credit, you need to select the guy who got given the quest and wait for the priest to talk about it. Once you have a quest, every time that guy enters the building the priest, smith, mage etc will either berate you for not completing it, or tell you how wonderful you were and give you the reward. If you have been given the quest again, I would guess that you have 2 members of the temple guild, and you have been doing your talking with the second dude who is eligible. All your guys and gals, when / if they join the temple guild will get this quest. All 6 of my party have given Medakwa a potion. Pity I found this out too late - only had one or two each on early quests and missed out on some experience (eg. ring of saints - once it's found the quest disappears off the list). Also toasted Scabban, and found that there were extra experience points for visiting him a second time in a quest (that opportunity permanently flushed).