Marketpress Fatal error: Call to undefined function wp_editor() .../plugins/marketpress/marketpress.

Hi!
I am finally setting up my MarketPress store on a second site in my multi-site and I am getting this error on the "presentation" tab. (Works just fine in the first store...)

Marketpress Fatal error: Call to undefined function wp_editor() .../plugins/marketpress/marketpress.php on line 5545

Any ideas? Thanks!