sdk manual: Important
The calling convention used in the functions exported by the shared TeamSpeak 3 SDK libaries is cdecl. You must not use another calling convention, like stdcall on Windows, when declaring function pointers to the TeamSpeak 3 SDK libraries. Otherwise stack corruption at runtime may occur.
after i changed all exports in your source to
[DllExport("**********", CallingConvention = System.Runtime.InteropServices.CallingConvention. Cdecl)]
it started without crash