Firstly, try and run some searches with some keywords relating to your problem (E.G. "viconia nothing to say" or "crash AR1234") and read the pinned topics before reporting bugs, to avoid asking the same question thirty times around. Modders often get annoyed when they have to answer the same question frequently!
You may also want to take a look at some Generic Common Problems before continuing, and perhaps read ESR's "How to ask questions the smart way".
We'll assume that you read the Read-me and/or the install instructions
1. Try to be specific...
"It doesn't work!!!!" doesn't help much.
My install CTD'ed when entering AR000X is good..
If you don't know the tech lingo, just describe it as best you can. "Jaheira's dialogue doesn't make sense." or "When I tried to go to Trademeet it broke."
2. Post your WeiDU and Error log.
More often than not, bugs are caused by incompatibilities or wrong install orders. Posting your Logs allows others to see where the problem may be and suggest a fix.
3. Good manners never hurt anybody.
Be nice. Don't expect help if your post says "Your f**king mod broke my install."
4. Multi Mod installs.
If you're installing many mods, don't single out a particular mod as the culprit! Unless you're really sure which mod is the problem, allotting blame will get you nowhere. There isn't a good answer to this problem. But people will do there best to help if they're not being held responsible for a problem not of their making.
