I think you’re experiencing 2 separate issues here, one of which is a recently-identified bug we’re working to address, and the other of which can be quickly fixed. Issue 1: a User can only use the File component to add Attachments to Tasks that that User is the Owner of. Issue 2: for the Skuid File component to work when Skuid is run from a VF page (using the skuid:page VF component), you have to make a local clone of the UploadImage VF Page that is in the SKuid Managed Package Looks like this is not in the tutorial for the File Component, but it should be. We’ll address this. There are actually 4 Visualforce Pages that are included in the Skuid Managed Package that you should make local clones of if you are going to use the skuid:page Visualforce component. These pages are: - ExportData - Include - UploadImage - Social 
To clone these pages, simply go to Setup > Visualforce Pages, and find each of these pages. Click to view each of them, and copy and paste the Visualforce Markup of each, exactly, into a new Visualforce Page with the EXACT same name and label, like so: 
