LuaSOAP problem in decoding response.

I'm trying to build a module that will access IDEone, which itself uses a SOAP interface. Here's the script I'm using to access it: http://sprunge.us/Xjjj?lua

This seems to work in that: a) it creates network activity and b) it gets a response that is sensible for the input. But something inside client.lua crashes while trying to decode, so this is what I get:

lua5.1: /usr/share/lua/5.1/soap/client.lua:96: Error while decoding: /usr/share/lua/5.1/soap.lua:239: attempt to index local 'o' (a nil value)

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://ideone.com/api/1/service" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns2="http://xml.apache.org/xml-soap" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><ns1:createSubmissionResponse><return xsi:type="ns2:Map"><item><key xsi:type="xsd:string">error</key><value xsi:type="xsd:string">OK</value></item><item><key xsi:type="xsd:string">link</key><value xsi:type="xsd:string">YqgSR5</value></item></return></ns1:createSubmissionResponse></SOAP-ENV:Body></SOAP-ENV:Envelope>

stack traceback:
[C]: in function 'assert'
/usr/share/lua/5.1/soap/client.lua:96: in function 'call'
junk.lua:3: in main chunk
[C]: ?

<?xml version="1.0" encoding="UTF-8"?>

Parsing that returned XML by hand I'm seeing what I expect:

error → OK
link → YqgSR5

Sure enough, if I hit http://ideone.com/YqgSR5 I have my humble little submission. It appears that the actual SOAP transmission and reception is doing fine.

How do I take this to the next step of not having the call function crash?

LuaSOAP version is 3.0 using Lua 5.1.5 running on Linux Mint 15.

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