Well, I am the developer of the Nicotine port.
The problem that gives you is strange, since in this moment it's logged and it's downloading information about the server, as the rooms list. There are a few options in the menu that they give you a major information of what happens, you must activate 'show debug info' and deactivate 'hide log window'. Do you may writting the information that gives it in this window?

This might be a bug in nicotine, so thank you for post this.

Best Regards.