i created a csv with some fields, everythins is all right, except for a date field...
In attachments the files of an user exported and the file to import.
You probably worked with the field in a spreadsheet. The field must be formatted to suit the date specification on your server and in mysql. Usually dashes are involved. Try exporting the field to see what your server wants but look at it using a text editor NOT EXCEL or LibreOffice.
Date fields are stored in an internal representation. You must supply the dates as text so they can be interpreted correctly. On output in reports, you can do what you wish in terms of formatting.
Make a CB list and use that to display the date associated with the user using a menu item.
To see how it is store, just do a save of your cb data using the cbjuice save option