:/ It has been noted by a number of players that two monsters are causing crashes in the mod - something to do with their animation sequences. Both of these monsters appear in Act III, specifically Lower Kurast, Travincal and Level 2 in the Durance of Hate.
:warning: The nature of these crashes is intermittent. Sometimes the mod will crash, other times it will work fine with those monsters. Kato is currently working on an interim patch version to alleviate these problems.
:D A new release version 4.2B which has these problems corrected has been released. Download it now from the download section.