To resolve this issue, follow the steps provided in the below article:
I also recommend you to install K-Lite codec pack by clicking the below link:
If you are still unable to burn DVD's, please provide the following information:
• What does the error message say?
• What is the file format?
• Is this happening to all Videos or just with a particular one?
• What version of RealTimes or RealPlayer is installed? (See https://customer.real.com/hc/en-us/articles/204039513)
• Do you have any security software installed (Norton, McAfee, AVG, etc.)?
The more specific you are, the better I will be able to assist you.