Array to string conversion

PHP Notice: Array to string conversion in /path/to/wp-content/plugins/wpsc-woocommerce/includes/admin/print_custom_form_field.php on line 31

Where line 31 is:

<?php if($custom_field_types->extra_info){?><p class="help-block" style="<?php echo $extra_info_css?>"><?php echo $custom_field_types->extra_info;?></p><?php}?>

And $custom_field_types->extra_info is:

{
	"custom_fields_extra_info_53": "Please insert your name.",
	"custom_fields_extra_info_54": "Please insert your email.",
	"custom_fields_extra_info_55": "Short description of the ticket.",
	"custom_fields_extra_info_56": "Detailed description of the ticket",
	"custom_fields_extra_info_57": "",
	"custom_fields_extra_info_58": "Please select priority.",
	"custom_fields_extra_info_98": "",
	"custom_fields_extra_info_99": ""
}

Same problem on line 84.

Temporarily disabling it by adding false && to the conditional:

<?php if(false && $custom_field_types->extra_info){?><p class="help-block" style="<?php echo $extra_info_css?>"><?php echo $custom_field_types->extra_info;?></p><?php}?>