The xml file you will fine in C:\Mach3 folder, if you are using the standard mill profile it will be called Mach3Mill.xml, if you made a custom profile it will be the name of that custom profile.
To attach the xml and code you use the additional options button on the reply page, you will probably have to rename the xml before the forum will accept it so if you copy from C:\Mach3 to your desktop and then rename it to pistolknight.xml it should be fine for attaching.
Hood