Cannot create ProtoField with ftypes.NONE

Hello,

i'm trying to create a dissector in .lua for Wireshark (1.10.7 x64) and i cannot add a field with ftypes.NONE, because Wireshark complains about "invalid ftypes".

So my question here is: Is this a bug, or is it supposed to be like that?

Edit: Sorry i forgot the sample code. Im trying to convert this old dissector written in c to lua: C-Code:

static hf_register hf[] = {
{ &hf_myproto, { "Data", "myproto.data", FT_NONE, BASE_NONE, NULL, 0x0, "myprotoPDU", HFILL}},
{ &hf_myproto_header, { "Header", "myproto.header", FT_NONE, BASE_NONE, NULL, 0x0, "myprotoHeader", HFILL}},
{ &hf_myproto_packet, { "Packet", "myproto.packet", FT_NONE, BASE_NONE, NULL, 0x0, "myprotoPacket", HFILL}}, 
...
}

Lua-Code:

local ncp = p_myproto.fields
ncp.hf_myproto = ProtoField.new("Data", "myproto.data", ftypes.NONE, nil, base.NONE, 0x0, "myprotoPDU")
ncp.hf_myproto_header = ProtoField.new("Header", "myproto.header", ftypes.NONE, nil, base.NONE, 0x0, "myprotoHeader")
ncp.hf_myproto_packet = ProtoField.new("Packet", "myproto.packet", ftypes.NONE, nil, base.NONE, 0x0, "myprotoPacket")
...

There are some more fields with uint16 and such, but they are working just fine, so i removed them here.

-Namikon