Disc cannot be burned

[Tier]

Trying to burn an audio disc from 3 FLAC files on my SSD, downloaded in "CD format". I get this error message: "None of the Tracks Could Be Added To The Audio Image. The Disc Cannot Be Burned." There is a new CD-R blank disc in the CD drive. I have Windows 10 64-bit updated to 20H2 on a Dell desktop PC. I can burn the disc with Windows Media Player but not with CDBurnerXP. It worked in the past. I have the latest version: 4.5.8.7128. What is wrong?

[Tier]

PS to above: The CDBurnerXP error log shows:

15/02/2021 16:32:18 (CDBurnerXP): System.IO.FileLoadException: The process cannot access the file because it is being used by another process. (Exception from HRESULT: 0x80070020)
   at Microsoft.Win32.Windows7.ICustomDestinationList.CommitList()
   at Microsoft.Win32.Windows7.TaskBarExtensions.AddTaskToJumplist(String title, String argument, String iconPath)
   at CDBurnerXP_Pro.modMain.LauchAfterAssemblyCheck(String[] args)

But there is no other process using the files.  So this does not help.

[Tier]

Still trying; disappointed that no one has replied.  The error log now shows a different error:

19/02/2021 15:13:53 (CDBurnerXP): System.Runtime.InteropServices.COMException (0x800402A7): Exception from HRESULT: 0x800402A7
   at RocketDivision.StarBurnX.StarBurnXClass.InitializeEx(String license, STARBURN_TRANSPORT transport)
   at CDBurnerXP.Burning.BurningEngine.InitialiseStarBurn()
   at CDBurnerXP_Pro.modMain.LauchAfterAssemblyCheck(String[] args)

So: why can I burn an audio disc with Windows media Player but not with CDBurnerXP?