When adding a Registration Package, you were asked for ”Number of Packages Available”. If you left that as 0, the package will show as “Sold Out”. To fix, go to Manage Event/Registration Packages and click on the sold out package. Set the number of packages available to the number of times you are willing to sell that package. For example, for a foursome, you might want to have 25 – 40 available.
If you set the Number of Packages Available to 10 and 10 packages have been sold on your site, the item will show as sold out.