I've tried to skim through all of this post, but its just really REALLY long, heh. I also posted something in the modding forum (because I imagine my problem stems from the graphics pack, since vanilla seems to work fine), but I never got an answer.
So to start from the beginning, I'm on x64 Arch Linux and I have the dwarffortress package from multilib installed. I then downloaded Ironhand's pack (the latest version, .495 I believe) and just unzipped all of it into the folder, of course overwriting the init from the vanilla installation and using Ironhand's init. I then generate a large region and embark and everything seems peachy. However, after several sessions, I'll eventually run into the problem (this can happen the first time after I come back to a new game, or the fifth time, it eventually happens every time I've made a new game). The problem is that whenever I use 'k' to look around, it crashes with a segmentation fault tell me that there is a texture that can't be found (can't remember the exact wording), I can get it for you guys if you really need it. This also happens when I try and build a workshop, or if I sometimes try and use 'q' to manage a workshop (that was already built before this starts). Basically any variety of actions can cause a crash and it almost always says missing texture or something like that.
The only way it seems I can fix this is if I reinstall the multilib dwarffortress vanilla package and then re-install Ironhand's graphics pack. But then the same problem crops up of course some time afterwards.
So not quite sure what to do and any help would be appreciated!