annoying creation of TRC file every time I run script

I'm using SAPNWRFC and everytime I run a script an XML tracefile is created.

In my sap.yml file I have:

   ashost: <my hostname>
   sysnr: "00"
   client: "000"
   user: <username>
   passwd: <pwd>
   lang: EN
   trace: 0
   debug: 0

Tracefile starts with:

   <?xml version="1.0" ?>
   <TRACE opened_at="2007-09-11, 12:18:57" time_zone="GMT" 
   ...
   ...
   <ENTRY thread="-1431543296" comp="RUNTIME" time="2007-09-11,    12:18:57">RfcRecord::fillField was invoked for RFCTYPE_TABLE
   </ENTRY>
   ..
   ..
   </TRACE>

It's probably something silly I'm doing.

It didn't happen with old SAP::RFC.