Yep.... $19.99 gets you a "safe copy" and it's fully functional and registered with CW, here:
https://shop.cakewalk.com/1244/uurl-4ab882pnpw If you don't have a registered and fully functional version, please refrain from disparaging commentary on CW's products or support as many features are turned off in the demo versions and there is no demo version of MC.
Get a working version and that should let you solve that issue easily. I wasn't aware that they provided support for demo versions. Perhaps that's why they haven't responded. Most folks get support in the forums and the response time can literally be a few minutes or less from users like us if you hit it at the right time.
For support.... read the manual and or hit F1 in the program for the help menu and try to figure it out yourself... you learn more that way, watch the tutorial videos on the cakewalk site, ask questions in the forum and users will help, last resort... go to the CW staff support if you have done everything else and nothing worked. (in that order)
You should be able to easily open the files from MC3 (man that's an oldie) in the new MC7. In addition there will be a lot of really nice improvements and add-ons that the bakers have included.