Glass Factory Obelisk unsolvable?

[ionarus]

Hi,
I went to the roof of the glass factory to solve the perspective puzzle where you look through the roof window and the yellow glass bottle is the start of the obelisk puzzle here. However I cannot move to a position where the whole line can be drawn. There is always a break between the bottle and the door frame which I cannot get over.

This is the closest perspective I can get, but still there is the gap:
http://imgur.com/6fqztID

When I move any more backwards, the gap closes, but the roof window is hiding parts of the bottle so I cannot start the tracking.

In walkthrough screenshots it looks much more closer and therefore solvable.
Anyone else having this problem? Is it a bug or do I miss something?

[MASTAN]

There's something you can do about it. Go down and examine the area and those bottles.

[ionarus]

Aaahhh... got, it. Thanks a lot!