Tnx for replying.
I have ATI Radeon 9600 video card on Ubuntu 9.04 with open source drivers that came with the distro. I'm aware that ATI drivers for linux are not so good as those for nVidia cards, and Ubuntu reps are a bit lagging behind with driver versions for ATI. I've tried my luck with proprietary drivers few times before, but since i ran into a whole series of problems with other programs, I decided to revert back to OS drivers cause, for me, they produce the most stable system performance.
Actually, I've found the entrance with brute force
by combing the map for an hour and a half (man, I love this game), and posted this topic cause when i started playing the game while ago, figured that I wont be able to finish the game without using that item, and so after scouring through the forums and finding nothing similar, decided to mention it to you.
I've encountered few other minor graphical errors/glitches (i.e. grid markings even if the TAB key isn't pressed, on some maps), but thats all due to the bad drivers as you mentioned. But nothing that prevents me from playing this beautiful game.
If I encounter something else I'll post it in this thread. Tnx for help. Cheers!