If you receive an error message, when you create your listing and enter a price, it is probably because you have chosen to trade via "Buy Now", and have entered a price that exceeds 3000 DKK.
When you create a listing, the system will automatically check off the "Buy Now" trade-form, when you fill out the price field. This is due to the fact that the price is perceived as a so-called "Jump at the offer" price.
Since it is not possible to create a "Buy Now" trade that exceeds 3000 DKK, you will receive an error message, if the "Buy Now" button is not deactivated.
You can therefore do one of two things:
1) Uncheck the "Buy Now" button manually by removing the check mark.
2) Select "Bids requested" instead of a fixed price. The listing will then show that you wish to receive bids on your item, and you can furthermore set a minimum price on the item instead.