Hi,
Yip, BigSwede has nailed it on the button 100%. The small flat bar on the left is used to extend the T-piece on the rear brake lines upwards. Take a look at the rear diff and you will see where it fits. The other part extends the rear track bar downwards to cater for the increased distance between the diff and the chassis. If this is not installed, the rear axle will pull to one side. Last but not least, the unistrut does not look like the correct part (unless it has changed). It is supposed to be a replacement centre cross member.
Check out the pic on the Calmini website and you will see what it supposed to look like.
http://www.pureisuzu.com/99-01_3_lift.htm
I hope this helps.
Cheers
Robert