INVALID_FIELD_FOR_INSERT_UPDATE

The error is this:
stdClass Object ( [created] => [errors] => Array ( [0] => stdClass Object ( [fields] => Array ( [0] => Name ) [message] => Account: bad field names on insert/update call: Name [statusCode] => INVALID_FIELD_FOR_INSERT_UPDATE ) ) [id] => [success] => )

Happens everytime i try to export a (in this case) update in a user, from Drupal to sf.
I still don't get how sf works completely, but any idea why this happens?

PS: I haven't been able to create something in sf from drupal.

thanks