I did do some maintenance on the calibre website, deleted some spam accounts, perhaps your's was one of them? If so, I apologize for the mistake. What was your username?
Make sure that the calibre install directory is in your PATH when you invoke ebook-convert (otherwise windows wont be able to find the needed DLLs).
Notice to all: I can not
provide assistance with DRM removal, for legal reasons, so please do not contact me about it.