A user keeps getting emails with these with Zimbra 6.0.3, and I was wondering if anyone might know what the issues is.

Code:
- <SyncError>
- <Request>
- <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
- <soap:Header>
- <context xmlns="urn:zimbra">
  <userAgent name="ZimbraConnectorForOutlook" version="5.0.2931.15" /> 
  <nonotify /> 
  <noqualify /> 
  <account by="id">5b3db55e-2921-49ad-83b5-bfb8d39769d6</account> 
  <authToken>0_d9852b083844cdb5864e2c34969fd38af6889681_69643d33363a35623364623535652d323932312d343961642d383362352d6266623864333937363964363b6578703d31333a313236343935343839383936343b76763d313a303b747970653d363a7a696d6272613b</authToken> 
  <nosession /> 
  </context>
  </soap:Header>
- <soap:Body>
- <FolderActionRequest xmlns="urn:zimbraMail">
  <action id="11" op="delete" /> 
  </FolderActionRequest>
  </soap:Body>
  </soap:Envelope>
  </Request>
- <Response>
- <soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope">
- <soap:Header>
- <context xmlns="urn:zimbra">
  <change token="5833" /> 
  </context>
  </soap:Header>
- <soap:Body>
- <soap:Fault>
- <soap:Code>
  <soap:Value>soap:Sender</soap:Value> 
  </soap:Code>
- <soap:Reason>
  <soap:Text>cannot modify immutable object: 3</soap:Text> 
  </soap:Reason>
- <soap:Detail>
- <Error xmlns="urn:zimbra">
  <Code>mail.IMMUTABLE_OBJECT</Code> 
  <Trace>btpool0-4068:https://63.246.1.74:443/service/soap/FolderActionRequest:1264793427947:ac372ea835298a67</Trace> 
  <a t="IID" n="itemId">3</a> 
  </Error>
  </soap:Detail>
  </soap:Fault>
  </soap:Body>
  </soap:Envelope>
  </Response>
  </SyncError>