Hi,
Supposing you are working with WebRatio 9 Platform, this kind of error could be returned if WebRatio is installed in a partition (e.g. C:) and the Workspace is stored in another partition (e.g. D:). This issue will be solved in a next update of WebRatio.
If it is the case, to avoid the error you could create a new Workspace in the default partition (e.g. C:) where WebRatio is already installed. To do that you have to choose another workspace path when you run WebRatio.
I hope this will help you.
Moreover if you are a student you can consider the WebRatio University Program. In fact you can obtain a free WebRatio 7 copy dedicated to teachers and students. For more details: https://www.webratio.com/site/content/en/university-program.