Need to store one of id of REST POST response for successive GET

I am new to Gatling.

Below is my post response:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> 3cee8bf6-3b57-11e8-8391-0242385363aa prasd34 PCTP Ethernet Port Termination Sure_REST_API_Test_network1:10.163.45.4:shelf-1:cardSlot-1:card:daughterCardSlot-1:daughterCard:port-1 Sure_REST_API_Test_network:10.163.45.4:shelf-1:cardSlot-1:card:daughterCardSlot-1:daughterCard:port-1 Level2 2018-04-08T23:34:10.526+05:30 2018-04-08T23:34:10.526+05:30 T0 displayedName Port 1/1/1 false baseMacAddress 00-00-00-00-00-02 false

My similuation is =>

val scn = scenario(“POST Query Senario”)
.exec(http(“Eq_Create”) // Here’s an example of a PUT request
.post("/equipments")
.headers(headers_10)
.body(RawFileBody(“post_payload.xml”)).asXML
.check(xpath("/Equipment/UUID").saveAs(“id”))
.check(status.is(201)))
.pause(5)
.exec(http(“GET_eq”)
.put("/equipments/${id}")
.headers(headers_10)
.check(status.is(200)))
.pause(3)

In the above i am trying to store the UUID field from post response and try to READ ( GET) same UUID .
But getting below ERROR

Simulation computerdatabase.BasicSimulation started…
Error on line 1 column 1
SXXP0003: Error reported by XML parser: Content is not allowed in prolog.
23:59:06.162 [WARN ] i.g.h.a.ResponseProcessor - Request ‘Eq_Create’ failed: xpath((/Equipment/UUID,List())).find.exists failed, could not prepare: Could not parse response into a DOM Document: SaxonApiException: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 1; Content is not allowed in prolog.

23:59:11.064 [ERROR] i.g.h.a.s.HttpRequestAction - ‘httpRequest-2’ failed to execute: No attribute named ‘id’ is defined