Ice Thread Pool problem

Hi!
I've a problem in developing project with Ice 3.3.1 vs CodeGear 2009 SP4, wich works on Windows XP SP3.
My client-server applicaion works with session factory, timestamp and garbage thread (demo Sessions).
I add method GetResult (std:string& s, Ice::Current &) to the class SessionI, which uses client application to get data from the server:

class SessionI : public Demo::Session, public IceUtil::Mutex
{
public:

    SessionI(const std::string&);

    virtual Demo::HelloPrx createHello(const Ice::Current&);
    virtual void refresh(const Ice::Current&);
    virtual std::string getName(const Ice::Current&) const;
    virtual void destroy(const Ice::Current&);

    virtual void GetResult (std:string& s, Ice::Current &);

    IceUtil::Time timestamp() const;
....
};

Class OraProxy:

class OraProxy: puclic Ice::Object
{
	private:
		char *lname;
		....
	public:
		GetParseString(string& result_string);
};
typedef IceUtil::Handle<OraProxy> OraProxyPtr;

Then i described method GetResultin module SessionI.cpp:

void SessionI::GetResult(std::string& s,const Ice::Current&)
{
	OraProxyPtr op=new OraProxy();
	op->GetParseString(s);
	...
}

In method GetParseString of class OraProxy I try to allocate memory for field lname using code:

void OraProxy::executing_statement(std::string& result_string)
{
	numcols = 3;
	lname=(char*)calloc(1,numcols*MAXFETCH*((MAXLEN+1)*2));
	....
	free (lname);
	result_string = ...;
}

Now about problem. When clients connect to the server, which started whith parameter Ice.ThreadPool.Server.Size=1, all works well, but very slowly. But when i make Ice.ThreadPool.Server.Size more,then 1, my server works some time and then falls with Access violation error while executing method executing_statement.

P.S. I change type of field lname to vector and try to allocate memory with method resize(), but nothing changed.

Regards.