Hi, can't find any posts dealing with this, sometimes it's not good to feel special!

Version 1.3.9f
Not upgraded but various mods:
Custom coded category tree
Column Grid Layout
Advanced Shipping
Easy Populate (basic)
Minimum Order (disabled)

Trying to set up a coupon to give 1 specified product (a bottle of Champagne X) free on the customer's next order. So they pay for the order as usual but when they add a bottle of the Champagne X it is free.

Coupon admin as follows:
Coupon amount: 100%
Coupon minimum order: 0
Free shipping: unchecked
Uses per coupon: 12
Uses per customer: 1

Start date: today
End date: end of the year


Restrictions:
Top category: deny
Product champagne x: allow

The problems:

1) When customer (test) goes to Information/Discount Coupon it progresses through the first page OK, accepting the code, and on to the second page, where I get an unwanted

Category Restrictions:
This coupon is valid for all categories.
(I have tried all sorts of configurations and cannot get anything other than this)

The product restriction is as I would expect, says Champagne X is valid.

2) The send button on this page does nothing (progress bar begins then gives up).

3) However, if I go to the cart, add some products including 1 bottle of Champagne X, and proceed to step 3 I'm told that the coupon has been successfully redeemed. Unfortunatley the TOTAL has been discounted by 100%, rather than just Champagne X, leaving £0 to pay. Rather more generous than I had intended!

Sorry about all the detail, it seemed better to be as exact as poss., and thanks for reading this far ... all help very gratefully received.