Single Insance Codeunit and XML Automation crashes Navision

Navision ver. 4.0 SP3, SQL database.
There is SingleInstance Codeunit1, which has SonicMQTransport Automation object.
SonicMQTransport is a DLL’a, which receives xml messages from Sonic queue and fires event OnXmlMsg(xmlDocument .IDispatch….) to Navision.

From Navision OnXmlMsg event, I take incoming xml document and parse it with another (not singelinstance) Codeunit2.ParseXML(xmlDoc) procedure.

Codeunit2.ParseXML() procedure parses xml, creates response xml and sends it back to SonicMQueue through SonicMQTransport.SendXMLMessage(xmlDoc…) procedure.

Problem is that after few transactions Navision stops receiving xml, event OnXmlMsg do not fire anymore. However, SonicMQTransport dll still works, because I can see incoming xml files are saving to folder (for debug purposes). Sometimes, Navision not only stops receiving xml, but closes without any error messages.
Furthermore, Task Manager shows that after each transaction Mem usage of finsql.exe increases 12-48kb, and on the last transaction Mem usage increases up to 100kb, and Navision stops receiving xml documents.

Actually, I have suspicions about Codeunit, which parses xml. I have noticed one strange thing. If I make response XML and send it back somewhere in the beginning of ParseXML procedure, Navision makes more transaction (let’s say 50). But If Navision covers more code, and goes deeper to other procedures and after creates xml document and send it back to queue, in this case only few transactions is possible (let’s say after 5 trans. Navision stops receiving xmls or even crashed without any error messages)

Maybe somehow I CREATE xml documents wrong. Do I have use CREATE(XML, TRUE) each time? Or Clear(Codeunit2) before parsing? I try to solve this problem two weeks already, and I think that tried everything, but no luck… Maybe there something that I don’t know working with Single Instance codeunits and Automation object..?

I would appreciate any help or ideas,
hxr

p.s. code sample

SingleInstance Codeunit1----------------------------------------------
* OnRun
CLEAR(SonicMQRegVBL);
IF NOT CREATE(SonicMQRegVBL,TRUE) THEN
  ERROR('RegVBL: Communication component not created');
recSetup.GET;
SonicMQRegVBL.broker:= recSetup."RegVBL Sonic broker";
SonicMQRegVBL.sendQueue:= recSetup."RegVBL send queue";
SonicMQRegVBL.receiveQueue:=recSetup."RegVBL receive queue";
SonicMQRegVBL.pwd:= recSetup."RegVBL password";
SonicMQRegVBL.uid:=recSetup."RegVBL user";
SonicMQRegVBL.messageTimeToLive:=0;
SonicMQRegVBL.dbgIncomingMessagePath:=recSetup."RegVBL debug inc. msg. path";
SonicMQRegVBL.Connect;

* SendXMLMsgRegVBL(VAR XMLDoc : Automation "'Microsoft XML, version 2.0'.DOMDocument";VAR XMLPropertiesDoc : Automation "'Microsoft XML..) 
SonicMQRegVBL.SendXmlMessage2(XMLDoc, XMLPropertiesDoc, 0, CorrID);

* SonicMQRegVBL::OnXmlMsg(xmlDocument : Automation "''.IDISPATCH";xmlProps : Automation "''.IDISPATCH")
codRegVBL.ParseXML(xmlDocument, SonicMQRegVBL.MessageId);

Codeunit2 ------------------------------------------------------------------------
ParseXML(varVar : Variant;MsgID : Text[1024])

GlobErrCode :='';
GlobErrText :='';
GlobVBKBID :='';
CLEAR(Cont);

IF NOT ISCLEAR(xmldomdocument) THEN CLEAR(xmldomdocument);
IF NOT ISCLEAR(XMLResp) THEN CLEAR(XMLResp);

CREATE(xmldomdocument);
CREATE(XMLResp);
xmldomdocument.load(varVar);

xmldomdocument.setProperty('SelectionLanguage','XPath');
searchString := 'xmlns:cst=''http://www.company.com/crm/customers''';
tmpVariant := searchString;
xmldomdocument.setProperty('SelectionNamespaces',tmpVariant);

MessageID := MsgID;

s:='cst:RegisterVBL/cst:CustomerInfo';
pxmlroot:=xmldomdocument.selectSingleNode(s);

{...Some parsing goes here...}

ExtractCustInfoToBufferRegVBL(tmpSMQGetCustomerInfo, tmpContactAltAddress, tmpAkc,
  WorkMode, Cont."Dok. tipas", VarDocumentID, GlobVBKBID);
  
IF GlobErrCode <> '' THEN BEGIN
 IF recSMQGetCustomerInfo.GET(tmpSMQGetCustomerInfo.EntryNo) THEN recSMQGetCustomerInfo.DELETE;
 MakeRegVBLErrXMLDoc(XMLResp,GlobErrCode,GlobErrText,GlobVBKBID);
 codADASComm.SendXMLMsgRegVBL(XMLResp, XMLPropertiesDoc, MessageID);
 IF NOT ISCLEAR(xmldomdocument) THEN CLEAR(xmldomdocument);
 IF NOT ISCLEAR(XMLResp) THEN CLEAR(XMLResp);
 EXIT;
END;

{...Some more parsing goes here..}

IF GlobErrCode = '' THEN BEGIN
  MakeRegVBLRespXMLDoc(XMLResp, GlobVBKBID, Cont."No.");
  codADASComm.SendXMLMsgRegVBL(XMLResp, XMLPropertiesDoc, MessageID);
END;

IF NOT ISCLEAR(xmldomdocument) THEN CLEAR(xmldomdocument);
IF NOT ISCLEAR(XMLResp) THEN CLEAR(XMLResp);

{End OF Proc.}