I remeber having that problem.. Mainly because of using new textures or so.. Try using a picture trasperent for the background. You can use photoshop for this (since photoshop is very helpful) or other cool/useful photo programs.. Mainly people use photoshop for transperent backgrouds..About the "Attach Function" broken. You should try to re-install SZS Modifier, if my method doesn't work tell me.