Green’s Dictionary of Slang

box n.2

[fig. use of farming jargon box, to mix up two herds or flocks by mistake; note also earlier in a box under box n.1 ]

[late 19C–1940s] (Aus./US) a blunder, a mix-up, a mess; a predicament.

In phrases

make a box of (v.)

[20C+] (Aus.) to make a mess of.