a. Granted, but there's always cygwin. Also, the concept is what's important, this could be done just as easily with a php script.
b. Your sollution would still mean having to go through all the files which use slash as the directory seperator and replacing them with a backslash. Also, that leaves you with exactly the same issue should you ever what to port the code back to unix. If you use the DIRECTORY_SEPERATOR constant you never have to worry about the issue again.