In this case the program would allow you to do the recording even if you need to do a long recording, check the information on Options/Recordings Tab and verify that you don't have any stop on silence, usually the free version would provide you all the features and tools, but wit a limited use of then.
If you still getting problems, would be better to send the request to the Technical Support Team https://www.nch.com.au/support/supportcontact.html?software=WavePad