Your level needs to be higher for you to be able to train and others having trouble with the tactics map in battles (backspace), check our taleworlds forum board. The expanded troop tree has very high level troops and dont confuse their tier number with their actual level. As for firearms - there are only the native firearms, which you can access through the cheatmenu (turn debug mode on in the mod Narutos advice. Floris is also pretty much finished, since we devs dont have the time to further develop it. Steam can also force compatability mode upon you, which will only allow up to 1GB Light and Darkness is closed source. Do note 32bit systems only allow 2GB RAM unless you apply the FAQ fix. Floris Expanded requires up to 4GB RAM depending on how well your system functions with the games engine.
Messed up textures are a direct result from RAM shortage. Floris 2.54 is for Warband hardware is unable to handle the mod. Means that you are using a wrong Warband version with a wrong Floris version. Get_object failed for texture:ext_itm_helmet_sar_t7_veiled_c_normal'