Parenting hinging problems

Hello all,

My first post on this forum. A client has requested that we create a spinning cube style animation, with various things mapped on to each side, jumping about etc. Sounds really simple. Only problem is, parenting and hinging layers together sometimes works, and sometimes goes really weird. Looks like some kind of display bug with lines flying off in all directions.

This machine doesn't have a decent Open Gl card, so I'm using software viewport rendering. I wonder if this is the problem?

Has anyone had similar difficulties? (It's C4 and it's got latest patch).

Thanks. If not, may have to use a 3d app for this.