Preview is the problem; it exports okay and has been reported. Use this version and it should be good in PV as well.
Go to OPTIONS | EDITING tab | Advanced. Choose None (CPU only). That should fix the issue for now... 
There's no mandate to purchase a new key if what you have works well. Newer releases can always be test driven unlicensed - to check out features and quirks.
Your paid release never expires and your license is good for any version that's released within six months of purchase.
Report specifics here on any issues you run across, listing the version #.