It's probably the Sony CD-RW CRX160E 1.1b drive. Its very old technology, and may not work correctly with the new method that Microstudio 4.0 uses to recognize drives and read/write tracks. Check the Tools menu, Default Drives command. If it shows No for anything, then the drive won't work. Please read the manual on this Tools menu command for how it works. 
I'm glad you have solved the problem. As Dale said, we have never had this problem reported before.
