Malformed Completion for an IO Write?

Everytime I try to send a completion without data in response to an io write request from the root port I get my altera core going down due to, I assume a malformed tlp. Below I have the origninal request header and my two tries at a response, neither of which work. Can anyone tell me what the problem is?

Original io write request:

header0 x42000001 (io write, length 1)

header1 x0000010f (tag 1, first be 1111)

header2 x00200020 (address for io bar x200020)

my response first try:

header0 x0a000000 (completion w/o data, length 0)

header1 x01080004 (completer id, byte count 4)

header2 x00000120 (tag 1, lower address x20)

my response second try:

header0 x0a000001 (completion w/o data, length 1)

header1 x01080004 (completer id, byte count 4)

header2 x00000120 (tag 1, lower address x20)