LOL - probably just went up.
I'm guessing that the problem is the chain bunches into a pile when you try and get it to thread through the tunnel. (assuming the HDI is similar to a conquest - which I would have no idea)
I also assume that you were able to get to the master links so there is a bit of space where you can function.
It is much easier to pull chain through than push it. I think if you would have pulled a bit of string or light rope as you pulled the chain out you could use it to pull the new chain in. I would try and get some string/rope up around the front axle to help me get the chain up there.
I've made some assumptions of the problem so I should ask: what seems to be the problem?