Hello there, Im sorry if the topic is not for here, but I didn't found somewhere else to post it! I'm having very strange problem with these two mods

I'm playing with CustomNPCs and Real train mod (MineCraft 1.12.2) and when

playing only with these 2 mods - no problems I can select the texture for Custom npc easily, BUT after that I'm placing My RTM Custom Train/Rail Pack (which works perfectly) 

when I'm spawning NPC and click the button for selecting texture (skin) it crashes with this (https://pastebin.com/fmmEkak) As you can see in the report there are only both these mods!

Very very strange huh? I dont know is the problem from RTM or Custom NPCs, but is there any fixes because I really want these 2 mods in my 1.12.2 world

I'll be thankfull. Have a nice day/night! Sorry for my English if its bad! 

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