I have this same issue and my Viking Conquest is un-modded. I can do the naval battle just fine, and the moment I start the Disembark sequence my boats spawn under hill terrain with all NPC spawns directly above on top of the hill. I can walk off the side of my pile of ships, appear on top of the hill and kill the NPCs ending the battle, however when the story takes me back to the overworld map and everything is black-textured,my ability to save disappears as all saves are gone, and I get the "Couldn't Save the Game" grey text message.
It is pretty surprising that Viking Conquest can handle whole sieges and bandit hideout instances, but the moment you try and spawn the post-naval skirmish on the island it baulks.
Code:
first_time = 1
texture_detail = 10
render_buffer_size = 15
max_framerate = 60
start_windowed = 0
use_pixel_shaders = 1
use_vertex_shaders = 1
fake_reflections = 1
show_framerate = 0
use_ondemand_textures_ = 1
use_ondemand_textures_mt = 1
disable_music = 0
disable_sound = 0
disable_frequency_variation = 0
cheat_mode = 0
enable_blood = 1
enable_edit_mode = 0
force_single_threading = 0
debug_mode = 0
display_width = 1920
display_height = 1080
display_bits = 32
antialiasing = 0
sample_quality = 0
alpha2coverage = 0
force_vsync = 1
shadowmap_quality = 0
shader_quality = 0
postfx_dof = 0
postfx_hdr = 0
postfx_autoexp = 0
flora_degrade_distance = 75.0000
flora_lod_detail = 2
use_instancing = 0
use_secure_connection = 0
max_number_of_connections = 16
look_for_server_on_this_machine = 0
music_volume = 0.1437
sound_volume = 0.7437
mouse_sensitivity = 0.5000
invert_mouse = 0
enable_lighting = 0
enable_particles = 0
enable_blood = 1
enable_character_shadows = 0
enable_accurate_shadows = 1
number_of_corpses = 0
grass_density = 0
combat_speed = 2
friend_combat_difficulty = 2
adapter_format = 0
reduce_combat_ai = 1
reduce_campaign_ai = 1
combat_difficulty = 2
display_labels = 1
display_targeting_reticule = 1
display_attack_direction = 0
turn_camera_with_horse_in_first_person = 2
verbose_damage = 1
verbose_shot_difficulty = 1
battle_size = 0.0000
attack_direction_control = 2
defend_direction_control = 1
lance_control = 2
anisotropic_filtering = 0
enable_environment_shadows = 0
verbose_casualties = 1
verbose_experience = 1
realistic_shadows_on_plants = 0
number_of_ragdolls = 0
gamma = 2.2000
character_detail = 0.0000
character_shadow_detail = 0.0000
control_mouse_movement_y_scale = 1.5000
blood_stains = 0
use_winmm_audio = 0
enable_version_check = 1
enable_aspect_ratio_control = 1
realistic_headshots = 0
auto_gfx_quality = 0
enable_gamepad_vibration = 1
