Socket programming problem

[matematik]

I'm using this class to connect to server:
bool ClientSocket:ovezi(String naslov, String port) {
// spremenljivke
WSADATA wsaData;
this->Povezava = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
int iResult;

// koda
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
MessageBox(NULL, "WSAStartup failed: " + iResult, "Napaka!", MB_ICONERROR|MB_OK);
return FALSE;
}

ZeroMemory( &hints, sizeof(hints) );
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;

iResult = getaddrinfo(naslov.c_str(), port.c_str(), &hints, &result);
if ( iResult != 0 ) {
MessageBox(NULL, "getaddrinfo failed: " + iResult, "Napaka!", MB_ICONERROR|MB_OK);
WSACleanup();
return FALSE;
}

for(ptr=result; ptr != NULL ;ptr=ptr->ai_next) {

// Create a SOCKET for connecting to server
this->Povezava = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (this->Povezava == INVALID_SOCKET) {
MessageBox(NULL, "Error at socket(): " + WSAGetLastError(), "Napaka!", MB_ICONERROR|MB_OK);
freeaddrinfo(result);
WSACleanup();
return FALSE;
}

// Connect to server.
iResult = connect( this->Povezava, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(this->Povezava);
this->Povezava = INVALID_SOCKET;
continue;
}
break;
}

freeaddrinfo(result);

if (this->Povezava == INVALID_SOCKET) {
MessageBox(NULL, "Unable to connect to server!\n", "Napaka!", MB_ICONERROR|MB_OK);
WSACleanup();
return FALSE;
}

return TRUE;
}

void ClientSocket:rekini() {
closesocket(this->Povezava);
WSACleanup();
}

String ClientSocket:obi() {
char recvbuf[512];
for (int i = 0; i <= 511; i++) {
recvbuf = '\0';
}
int iResult = 0;
iResult = recv(this->Povezava, recvbuf, 512, 0);
if ( iResult > 0 ) {
String for_ret = recvbuf;
return for_ret;
} else if ( iResult == 0 ) {
this->Prekini();
return "";
} else {
MessageBox(NULL, "recv failed: " + WSAGetLastError(), "Napaka!", MB_ICONERROR|MB_OK);
return "";
}
}

bool ClientSocket:oslji(String za_poslat) {
int iResult = send(this->Povezava, za_poslat.c_str(), (int)za_poslat.Length(), 0 );
if (iResult == SOCKET_ERROR) {
MessageBox(NULL, "send failed: " + WSAGetLastError(), "Napaka!", MB_ICONERROR|MB_OK);
this->Prekini();
return FALSE;
}
return TRUE;
}
And this is my code:
ClientSocket test;
test.Povezi("pop3.mail386.com", "110");
String dobitev;
dobitev = test.Dobi();
test.Poslji("USER nekdo");
String dobitev1;
dobitev1 = test.Dobi();
test.Poslji("PASS krneki");
dobitev = test.Dobi();
test.Poslji("quit");
dobitev = test.Dobi();
test.Prekini();

When I call test.Dobi() for first time it works fine, but when I call it again, it doesn't work. It stops at iResult = recv(this->Povezava, recvbuf, 512, 0);.
What's the problem?