Bobbin housing of my Janome QC 6260 keeps jamming?

Recently I had some trouble with the bobbin housing of my Janome Quilter's Companion 6260. The housing kept slipping past the "knob" it rests against, causing it to Jam. Since then the entire lower "drive unit" (if you can call it that) of the bobbin seems to Jam. I have tried running the sewing machine without thread and without the bobbin in place, and even then (so without any load) at full speed after a few seconds the machine starts to make a loud rattling noise down by the bobbin. The turning slows and stutters and then the machine stalls. The display shows "Lo" (which means the machine overloaded and needs to cool down)
Can anyone help me with this, is there something broken? Or do I have to re-adjust it?

I'm in the midst of making a quilt for my baby daughter and now I'm stuck...
Help please!