With both new parts about the only suggestion is to make sure you are hooking the hose to the adapter evenly, if it's "cocked" a little it will pop right off. I'm sure you know to pull the outside part on the hose down while attaching then push up a little. Try pulling gently on the discharge hose after you atttach it to make sure it's secured good.

The reason I say that is several years ago my aunt let me use her portable washer while I was having a washer & dryer hookup to be installed in a house I bought without a utility room. Had never seen or used one, got a wet face more than once :P
Nat