Error message on with WP version 3.7.1

I just installed WP Easy Columns on my friend’s blog (that is in its beginnings) on WP version 3.7.1.

I am getting this error message: “Notice: has_cap was called with an argument that is deprecated since version 2.0! Usage of user levels by plugins and themes is deprecated. Use roles and capabilities instead. in /webspace/12/78156/ushmidosaja.com/wp-includes/functions.php on line 3017”

I’ve used WP Easy Columns in the past, on other sites, but not with 3.7.1… is that the cause of this error?

HELP! I love your plugin, but I don’t know how I can use it with the current version of WordPress.

Thank you in advance!

Cheers,
Ana

http://wordpress.org/plugins/easy-columns/