ROIs not appearing in Denoising window

To whom it may concern, 

I have been trying to analyse a data set, containing 438 subjects, with 4 sessions each. I registered some regular ROI files, as well as two atlas files. When I ran the Denoising step, I selected the 'do not overwrite option', as I had already performed the step on three subjects. When I opened the Denoising window, non of the ROIs that I had registered were appearing in the window. These ROIs are vitally important to my research. What do I need to do to make it so that the ROIs that I want are actually analysed?

Kind regards, 
Romke Hannema