w/ cck-6.x-2.2 & gmap-6.x-1.1-rc1 - D6.10, Apache/2.2.11, PHP/5.2.8, MySQL 5.1.30:

have gmap_cck field (in a cck group) activated for a bio node, registration that does include other cck text fields (2) for the bio type - but not the gmap_cck field - following fatal error occurs after new user registration, or any other time attempting to save bio node:
Fatal error: Call to undefined function gmap_cck_content_is_empty() in D:\xampp\htdocs\610test\sites\all\modules\cck\content.module on line 900