"number of columns is not constant" tells you that you have 7 header columns but only 6 columns of data.
Unless you are using a very old version of Moodle, you do not need to specific the type column for enroling: if for some reason you do, then you have to put some data in the column for each user row.
Unless you are using a very old version of Moodle, you do not need to specific the type column for enroling: if for some reason you do, then you have to put some data in the column for each user row.