not a valid MySQL result,, activate_ not creating tables

Hi, in most cases my plugin works fine but a few (3) users report an error that seems to suggest that the neccesary tables aren’t being created when the plugin is activated. :-/, could it have something to do with ABSPATH & upgrade-functions.php? or dbDelta()?

I have:
add_action('activate_aStickyPostOrderER/astickypostorderer.php', 'croer_install');

…

//DB
$croer_db_version = "0.12";

function croer_install () {
   global $wpdb;
   global $croer_db_version;
   $table_name = $wpdb->prefix . "croer_posts";
   $meta_table_name = $wpdb->prefix . "croer_meta";
   // if create from scratch
   // this orders POSTS by cat or tag
   $sql = "CREATE TABLE " . $table_name . " (
			croer_id bigint( 20 ) NOT NULL AUTO_INCREMENT ,//etc...);";

	$meta_sql = "CREATE TABLE " . $meta_table_name . " (
			cmeta_id bigint( 20 ) //etc...);";

   if($wpdb->get_var("show tables like '$table_name'") != $table_name) {
      require_once(ABSPATH . 'wp-admin/upgrade-functions.php');
      dbDelta($sql);
      add_option("croer_db_version", $croer_db_version);
   }
   if($wpdb->get_var("show tables like '$meta_table_name'") != $meta_table_name) {
      require_once(ABSPATH . 'wp-admin/upgrade-functions.php');
      dbDelta($sql);
      add_option("croer_db_version", $croer_db_version);
   }
   // in case of upgrading
   $installed_ver = get_option( "croer_db_version" );
   if( $installed_ver != $jal_db_version ) {
      require_once(ABSPATH . 'wp-admin/upgrade-functions.php');
      dbDelta($sql);
	  dbDelta($meta_sql);
      update_option( "croer_db_version", $croer_db_version );
  }
}