Marketpress Issues - Digital Downloads

Hi

I simply want to give away my plugin for free, using Marketpress.

http://tradr.com/order/item/tradr-products-1-1/

Problems encountered so far:

- A new user tries to check it out but gets the message: Sorry, there is a per order limit of 1 for "Tradr Products 1.1". They are selecting 1 but this message still occurs
- I can't supply the buyer with different compression formats ie: tar, zip (windows), rar, zip (mac)
- I can't supply for the same product previous download versions. ie: 1.1, 1.11
- They had to enter shipping details (fixed in latest release)
- It is FREE !!! Yet, if the order has the "sorry there is a per order limit..." error it says please choose payment method. IF the product is 0.00 in price, can the 0.00 be replaced by the word 'FREE' and be handled a little different by marketpress?

Cheers

Johnny