Mmmm!
It is difficult to tell from that image alone.
There seems to be much customisation involved or the image is not at actual size. Even when I use large amounts of zoom in my browser I cannot get the New Topic, People and Options links to look like yours. While you don't complain about missing forum name or description, I see no trace of either in your image. On top of that it would appear the code for the player is inappropriate as it shows an incomplete scroll bar that is intended to have more vertical space than has been provided. Does you image show the full height and and width of your window above the links you can see?
Without more information, it may be that you do need a member of Nabble staff to rescue you and reset all your customisations.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.