To make my life easier and to get the fix ready quicker please follow this guide:
So, when opening a new topic first please make sure the bug is not already reported, then:
1. MOST IMPORTANT! Make a screen of the error (if any). Use Lighshot or similar programs and just post the link to the image.
2. Explain the steeps to reproduce the bug or error. May not seem important to you but it can help a lot to understand exactly what you clicked or what option you chose, what is your skill level, you have or not items required, etc.
Reference to Runescape Wiki, Item ID, NPC ID etc may be also helpful in some cases.
Thanks for your contribution in making the server a better place!