It's likely to be as simple as dumping CDRWin 4 and going back to CDRWin 3.8D which is totally reliable. CDRWin 3.8F is also good for burning but there is a glitch that may affect you in that it takes a long time to load and ties up other resources - screwing up, for example, subsequent dial-ups.

Let us know if that works, it has worked for oothers who have burned coasters with 4.0