A new update on (as far as i know, only) the x86-64 branch causes this, the original fesiug's edit and the original EPMS to crash. On the original's workshop page I've found a fix posted by a user called @XDforeth this has worked for me and some others it seems judging by the comments

引用自 XDforeth：

Hey guys, you may try this method to fix the problem. At least it worked for my gmod (64 bit).
But I don`t know if it will cause potential new problems.

1：Open the following directory of your gmod files:
\steamapps\common\GarrysMod\garrysmod\gamemodes\sandbox\gamemode

2：Find out and read the LUA file called "editor_player.lua"(create a backup for it before we start)

3：Remove the following code(begins at line 271):

concommand.Add( "playermodel_selector", function()

for id, icon in pairs( g_ContextMenu.DesktopWidgets:GetChildren() ) do
if ( !icon.WidgetClass or icon.WidgetClass != "PlayerEditor" ) then continue end

-- We gotta have this at the point of creation for some reason
g_ContextMenu:SetMouseInputEnabled( true )

-- Create the window
icon:DoClick()

-- Make it appear outside of the context menu
icon.Window:SetParent()
icon.Window:MakePopup()
icon.Window:Center()

break
end

end )