I have a bug report for the full game, which I played on IFDB.
I got the figure from the rift in Gareth's office, and I went through the blue rift. When I realised it transported me back to the beginning, I went back to get the plank and the bar, in case I needed them again.
Later, when I got the Diagnose utility, I went back to diagnose the blue rift. However, when I got back to the throne room, the bar was already between the columns, but when I tried to put the plank on it, the game couldn't find the bar. But when I tried to put the bar I was holding between the columns, the game said I couldn't because it was already there.
After trying a few times, I went to the green pool and my clone joined me again. Then, I somehow managed to put the bar between the columns and put the plank on top of it; I'm not really sure how I did it.
When I got up to the balcony, there was another robot monkey there, which gave me another figure (I had already given the first one back to Gareth), but for some reason the blue rift didn't appear again.
What probably happened is the game set a flag or flags incorrectly. Please fix this.
PS. The reason I'm reporting the bug here is because I thought you would be more likely to see it.