thanks for your help.
I put some messages inside the ftp class and discovered that the problem is in the call at the proc "OpenFTPConnection" where i cannot get a Handle from the internetConnect.
I tried to retrieve the error but I can't :

   This.GetExtendedError()
      IF lnConnect_Handle = 0
	=MessageBox(Transform(this.GetExtendedErrorCode())+Chr(13)+Transform(this.GetExtendedErrorMsg()),0,"1")
         RETURN .F.
      ENDIF

>What error you get after calling method OpenInternet()?
>?this.Ftp.GetExtendedErrorCode(),this.Ftp.GetExtendedErrorMsg()
>
>MartinaJ
>
>
>>here is lines of code :
>>

>>If !(Type("this.ftp") == 'O' and !IsNull(this.ftp))
>>	this.Ftp = createobject('ftp_service')
>>	this.ftp.cProxyPort = zProxyPort && 3128
>>	this.ftp.cProxyHost	= zProxyIp && 10.4.50.10
>>	If !Empty(zProxyip)
>>		this.ftp.cProxyProtocol = zProxyProtocol  && "http"
>>	Else
>>		this.ftp.cproxyProtocol = ''	
>>	EndIf 	
>>EndIf 
>>
>>this.statoConn = this.Ftp.OpenInternet(zUserFtp, zPwFtp, zFtpAddress, zFtpPort)
>>
>>

>>
>>
>>
>>>How you set cProxy???? properties on FTP object?
>>>
>>>MartinaJ
>>>
>>>
>>>>I tried but without success :(
>>>>
>>>>I installed a filezilla ftp client on that pc and it works with these settings :
>>>>
>>>>proxy FTP = none
>>>>
>>>>Generic Proxy : connection method = http/1.1
>>>> host proxy = 10.4.50.10
>>>> proxy port = 3128
>>>>
>>>>What should I do to make my program working ?
>>>>
>>>>thanks again
>>>>
>>>>
>>>>>Hi Alessio,
>>>>>
>>>>>Check cProxyProtocol property in help...
>>>>>
>>>>>MartinaJ
>>>>>
>>>>>>Hi Michel, sorry for disturbing you, but I don't know what to do for connecting to a ftp server from a under proxy client.
>>>>>>
>>>>>>I'm using the Robert Abram ftp service V.2.0.9 and it works fine without proxy but I don't know what to do for bypassing the proxy
>>>>>>
>>>>>>actually I call the openinternet function in this way
>>>>>>
>>>>>>

>>>>>>	this.Ftp = createobject('ftp_service')
>>>>>>	this.ftp.cProxyPort      = zProxyPort  && 3128
>>>>>>	this.ftp.cProxyHost	= zProxyIp   &&  10.4.50.10     
>>>>>>
>>>>>>       this.connStatus = this.Ftp.OpenInternet(zUserFtp, zPwFtp, zFtpAddress, zFtpPort)
>>>>>>

>>>>>>
>>>>>>well, i can't connect
>>>>>>
>>>>>>what should I do to make it working ?
>>>>>>
>>>>>>Thank you so much
>>>>>>Alessio