WordPress Child Theme – twentyeleven

your @import doesn’t look malformed. this is what i have on a live site that is running a twenty eleven child theme.

/*   
Theme Name: A Twenty Eleven Child Theme
Description: my child theme
Author: helgatheviking
Template: twentyeleven
Version: 1.0

*/

/* Reset browser defaults */
@import url('../twentyeleven/style.css');

so assuming that twentyeleven is in the same folder wp-content/themes as your child theme… this should work. did you clear your cache?