It looks like you clicked on the pencil icon 
of a dataset to reach the “Edit Attributes” functions. The server is unable to load that data, possibly because of a metadata problem or some server side problem. You could try making a copy of the history in your own account there to see if that resets the metadata. If not, you’ll need to contact an administrator.
The administrators of the repeatexplorer public Galaxy server do not follow this forum, and it is difficult for others to help more, especially for any actual technical server-side problems. Instead, please try contacting them directly via email.
Quote from there website: