Connecting Dropdown box to Dataset

Having created a dataset of Opponent Clubs I am trying to link a Dropdown box in a form I have constructed so that a Club Name can be selected and then written to another dataset. According to all instructions this is an easy and standard process. However, although the dataset is sitting in the Database list when I attempt to Connect to this data the Dataset does not appear in the list of available datasets. The only dataset that appears in the choices is the one I am writing to from the form. There must be a simple answer but I cannot see it.Any ideas ?