Yeah, thanks for the info, but I'm afraid that you didn't get what I'm saying.

Here´s the code for analysis.

thisform.tcpClient.object.Close()
thisform.tcpClient.object.Connect()
llShutdown = .F.
** SET STEP ON 
= INKEY(0.2,"H")
IF thisform.tcpClient.object.State = 7 &&Connected
	thisform.sentCommand="PING"
	thisform.lblStatus.Caption="Status: Sending command to server..."
	thisform.tcpClient.object.SendData(thisform.sentCommand+CHR(13)+CHR(10))	
	= INKEY(0.5,"H")		
	thisform.lblStatus.Caption = ALLTRIM(UPPER(thisform.serverMessage))	
	IF ALLTRIM(UPPER(thisform.serverMessage)) = "OK!"
		i = 0
		llStop = .F.
		DO WHILE i < 60 AND NOT llStop
			thisform.tcpClient.Object.Close()
			thisform.tcpClient.object.Connect()
			= INKEY(0.5,"H")
			IF thisform.tcpClient.object.State = 7 &&Connected
				thisform.sentCommand = "PING"
				thisform.tcpClient.object.SendData(thisform.sentCommand+CHR(13)+CHR(10))					
				= INKEY(0.8,"H")
				IF ALLTRIM(UPPER(thisform.serverMessage)) = "OK!"
					i = i + 1 
				ELSE
					IF NOT llDesligando
						thisform.lblStatus.Caption = "Status: The server is being shutdown..."
						= INKEY(15,"H")
						i = i + 1 
						llShutdown = .T.
					ELSE 
						thisform.lblStatus.Caption = "Status: Server successfully shutdown"
						llStop = .T.
					ENDIF 
				ENDIF
			ENDIF 
		ENDDO
		IF NOT llStop
			thisform.lblStatus.Caption = "Status: Timeout occurred while sending command"
		ENDIF 
	ELSE 
		thisform.lblStatus.Caption = "Status: Server offline"
	ENDIF 	
ENDIF 
WAIT CLEAR 

Well, notice the commented SET STEP ON there? when I run the code ignoring that line, server never returns anything. Whenever I uncomment the SET STEP ON line, server does return the OK! to the serverMessage property.

Here's the code for tcpClient.dataArrival:

*** ActiveX Control Event ***
LPARAMETERS bytestotal
lcServerMessage = SPACE(bytesTotal)
thisform.tcpClient.object.GetData(@lcServerMessage)
thisform.serverMessage = lcServerMessage

What is the problem here, then?

TIA again!