From IvanWiki

Known issues in version 0.50

• There are a whole lot of typos and grammatical errors!!
• Well, they don't crash the game so don't worry too much ;)

• Reading a scroll of harden material crashed the game!
• If you're carrying corpses, this inevitably happens. So don't carry corpses or just drop them when you use the scroll.

• Game froze when praying to Silva on Gloomy Cave level 6
• Praying to Silva on GC6 leads to an infinite loop. Don't pray to Silva on that floor.

• Some of the keys on my keyboard don't seem to work...
• This can be a critical problem playing IVAN (especially when you use a multilingual keyboard with different scancodes). Some variants of IVAN, such as IVAN 3D, provide solution on this problem, or maybe you can try using some key config software.

• Eating pea soup on the World Map crashes the game!
• Go into a town or dungeon before eating pea soup, or consume something else if you're in need of nourishment that badly.

• Segmentation fault on
  • Linux version 2.6.24-22-generic (buildd@vernadsky) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) (Ubuntu hardy heron), often when using stairs, always when trying to load savefiles. (see Talk:Known Issues#Strace) Always when going upstairs from the mother carnivorous plant.

• source doesn't compile on (insert your OS here)
  • Linux version 2.6.24-22-generic (buildd@vernadsky) (gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)) (Ubuntu hardy heron)

In file included from ../../FeLib/Include/save.h:25,
                 from bitmap.cpp:18:
../../FeLib/Include/fearray.h:37: error: invalid use of constructor as a template
../../FeLib/Include/fearray.h:37: note: use ‘fearray<type>::fearray’ instead of ‘fearray<type>::struct fearray<type>’ to name the constructor in a qualified name
../../FeLib/Include/fearray.h:45: error: invalid use of constructor as a template
../../FeLib/Include/fearray.h:45: note: use ‘fearray<type>::fearray’ instead of ‘fearray<type>::struct fearray<type>’ to name the constructor in a qualified name
make[2]: *** [bitmap.o] Error 1

• • This error can be easily remediated by following the instructions in the notes. It happens several times.