I cannot write to the disc when I drag and drop files. Or I get an error message telling me that the file is already ready for writing onto the disc.

This occurs when the Windows XP recording option is enabled, so you cannot write by dragging and dropping files to InstantBurn. The icons appear transparent in the folder. Disable the Windows XP recording option the follow the steps below.

1. Right click on the drive in "My Computer", and then select "Properties". 
2. Open the "Recording" tab, then disable (uncheck) the "Enable CD recording on this drive" option.
3. "Apply", then click "OK" to close the Properties window.