How Can I Restart in Windows Using a Script?
This works just using applescript. replace login_password with your login password.
Also make sure the path to BOOTCAMP is correct (it should be). Save as an application and open it when you want to reboot into BootCamp. This is two lines of code...

do shell script "bless -mount /Volumes/BOOTCAMP/ -legacy -setBoot -nextonly" password "login_password" with administrator privileges

do shell script "shutdown -r now" password "login_password" with administrator privileges