I think the issue is how you are setting the classpath property. Rather than this:
classpath="D:\Liquibase\Drivers\sqljdbc4.jar"
It should be this:
classpath=Drivers/sqljdbc4.jar
The path should be relative to the current directory rather than absolute. This is a good practice anyway if you intend to work with other developers on different machines.
Also the documentation for the liquibase.properties file may be a little off - it says that the properties file should be name:value, but I'm pretty sure it should be a standard java properties file, with name=value (equal sign rather than colon)