When importing sites into Website Pro it is recommended that you use All-in-One WP Migration Plugin. However, the free version of this plugin has size limitations (64MB maximum). If you want to import a site larger than 64MB into Website Pro, you have a couple options:
Buy the All-in-One WP Migration Unlimited Extension for $69 (this is a one time cost that can be used on unlimited sites).
Import your site using one of the many other WordPress migration plugins.