Нельзя писать внутрь моста/переходника хука. Для установки перехвата можно использовать HiHook патчера patcher_x86.dll или API из Эры:

function Splice (OrigFunc, HandlerFunc: pointer; CallingConv: integer; NumArgs: integer; {n} CustomParam: pinteger; {n} AppliedPatch: ppointer): pointer; stdcall;

Original function address (OpenBik first command address)
Your handler address
Calling convention of OpenBik function:

// Left-to-right
    CONV_PASCAL = CONV_LAST,

    // Left-to-right, first three arguments in EAX, EDX, ECX
    CONV_REGISTER = -102,

    // Right-to-left, caller clean-up
    CONV_CDECL = -103,

    // Right-to-left
    CONV_STDCALL = -104,

    // Right-to-left, first argument in ECX
    CONV_THISCALL = -105,

    // Right-to-left, first two arguments in ECX, EDX
    CONV_FASTCALL = -106,

Number of original function arguments, including those in registers
Two NULL arguments

Your handler must have STDCALL convention and accept void* OrigFunc argument + all other arguments in the same way, as original function would accept