First of all you need to use a Pc speaker with a high CHA score and Int above 10, best if 14+ for CHA, and the Pc must have invested some skill-points in skills like Diplomacy, Bluff, Intimidate, Gather Information & Sense Motive. The higher the score the better.
1.when my characters go to the black jay's meddow at night, they find corl but they can only say "what are you doing here" and then "go home" and so i cannot solve the quest.
There are two ways to solve this quest: Talk to everybody again and use the skillls Intimidate & Sense Motive on Corl, you will then get the proper dialouge options,
OR, if your skills are low or your PC low on CHA & INT : Pick up a sample of the plants on the ground in Black Jay's garden. It's a strange plant you haven't seen before. Then take it to Jaroo (the village Druid) and ask him about it. He'll tell you it's poisonous. You now have the evidence you need, return to Corl and confront him again. Voila !!
2.In the inn - only the two characters with which i began the game can speak to tuperello (drinking contest), and they are the weakest. how can i force Elmo to speak to him, so that he accepts the quest?
Only the Pc's you have made YOURSELF can initinte dialouge with Npc's. This goes for the entire game, so Elmo (and all the other hirelings) can never start talking. He might say something in special places, like when he meets his brother Otis in Nulb. So this quest must be solved with one of your two Pc's.
Start the talk with your PC w/ the most Hit-Points. Do you have a Cleric or Druid for healing ? Good if you do. If your 'drinking' PC is too weak and drops down, heal him back to full health with spells or potions then talk to Tuporello again. You won't win untill ALL contestants are down, so if Tuporello drops you might have to heal him too, just a bit to continue the contest.
You can also wait a few levels before completing this quest, it will be a lot easier at lvls 3-5 (or higher
) but you'll receive less XP then.
3.Cupid's Arrow- I cannot tell filliken that I've spoken to jaroo about his mourning. He says something like "How could say this about my beloved Melene, she reminds me so much of her mother. and you remind me of my horses' ass". I didn't say something like this. How do I finish the quest??
Here you have made some kind of blunder i think.
To get THIS ANSWER : "How could say this about my beloved Melene, she reminds me so much of her mother. and you remind me of my horses' ass" you have said something bad about Meleny. Are you Evil ?
This can sometimes happen if the two marriage quests are tempted at the same time, or you're 'speaker' is Low-INT-Low-CHA-Low-SKILL. You probably said (in Marrying Meleny) "Come on, she's ripe for the picking" This will make Filligan mad at you. To try to set things straight you should consentrate on one quest, re-try all dialouge options with a high CHARISMA, self-made PC. A high Bluff & Diplomacy skill let you through this dialouge a lot easier.
If you haven't yet started to court Meleny, do so. You need a Male Pc with Cha over 13 (+2 or better) and/or high Diplomacy and some Gather Information skill. She will NOT be courted by an Evil Pc though unless the CHA & skills are VERY high.
Lastly, save your game often and run through all possible dialoge options. Try to come back at higher levels and make sure your party have 1 'Speaker' for all the talking quests. And have Fun