Qatium requires the upload of all the Shapefiles. This includes the .shp, .shx, .dbf and .prj files. Please note that some modeling packages do not create a .prj file when exporting data to Shapefiles.
If all the required files are present, the problem might be that all files of the same layer don't have the same name. For each layer there must be one file per extension with the same name.
E.g.: for the layer example there must be the following files: example.shp, example.dbf, example.shx, example.prj
If the problem persists, contact us.