How to run dos commands from Notepad++ Execute command

Question

I've written a small script in the Notepad++ Execute textarea (hotkey F6)

npp_switch Main.java
cd ..\..\..\
javac -sourcepath src -classpath classes;lib\*.jar src\com\myfirm\*.java -d classes
java -classpath classes;lib\*.jar com.myfirm."$(NAME_PART)"

It requires a class in the same directory that ends with Main.java name. However, it fails if classes directory is not found at the level of src directory. All I need to do is

mkdir classes

but the dos commands (other than cd and javac/java) dont seem to work. Any thing I'm missing?