List of files with filename letter case errors (crashes game on Linux):
graphics/Steel Cardinal/weapons/SC_Ion_Mortar_hardpoint_base.png
graphics/Steel Cardinal/weapons/SC_Ion_Mortar_turret_base.png
graphics/Steel Cardinal/weapons/SC_Ion_Mortar_hardpoint_recoil.png
graphics/Steel Cardinal/weapons/SC_Ion_Mortar_turret_recoil.png
graphics/Steel Cardinal/weapons/SC_Ion_Mortar_hardpoint_base.png
graphics/Steel Cardinal/weapons/SC_QuadAA_hardpoint_base.png
graphics/Steel Cardinal/weapons/SC_QuadAA_turret_base.png
graphics/Steel Cardinal/weapons/SC_QuadAA_hardpoint_recoil.png
graphics/Steel Cardinal/weapons/SC_QuadAA_turret_recoil.png
graphics/Steel Cardinal/weapons/SC_TwinAA_hardpoint_base.png
graphics/Steel Cardinal/weapons/SC_TwinAA_turret_base.png
graphics/Steel Cardinal/weapons/SC_TwinAA_hardpoint_recoil.png
graphics/Steel Cardinal/weapons/SC_TwinAA_turret_recoil.png
graphics/Steel Cardinal/weapons/SC_Gamma_Blaster_hardpoint_base.png
graphics/Steel Cardinal/weapons/SC_Gamma_Blaster_turret_base.png
graphics/Steel Cardinal/weapons/SC_Gamma_Blaster_hardpoint_glow.png
graphics/Steel Cardinal/weapons/SC_Gamma_Blaster_turret_glow.png
Those are name cases as given in source. Alternatively you may edit source to mach actual case.