Looks like some of the configuration items may be missing from the store's database. Pull up configuration group 0 (note the URL, it may have to be typed in manually) and see if the following are present for the store in question...
Attachment 12680
Note especially the option for "text prefix" (TEXT_PREFIX). This one is missing (take a peek at the "text" attribute on the product page).
SQL to add these three options if missing (only pick the ones you need).
Code:
INSERT INTO `configuration` (`configuration_title`, `configuration_key`, `configuration_value`, `configuration_description`, `configuration_group_id`, `sort_order`, `last_modified`, `date_added`, `use_function`, `set_function`) VALUES
('Product option type Select', 'PRODUCTS_OPTIONS_TYPE_SELECT', '0', 'The number representing the Select type of product option.', 0, NULL, now(), now(), NULL, NULL),
('Upload prefix', 'UPLOAD_PREFIX', 'upload_', 'Prefix used to differentiate between upload options and other options', 0, NULL, now(), now(), NULL, NULL),
('Text prefix', 'TEXT_PREFIX', 'txt_', 'Prefix used to differentiate between text option values and other option values', 0, NULL, now(), now(), NULL, NULL);