B4R Question Byte() to string, string to byte in http request

dim a() as byte
a=byteconvert.StringFromBytes(Queue.FirstItem)
Log(a) 'here I see the expected number, for example: 1234
gotoweb(a)

Sub gotoweb (a() As Byte)       '  Sub gotoweb (a() As string)   '  declaration "Sub gotoweb(a() as string)" is not functioned. I get the same error as with: a() as byte
    Log(a) 'here I see the expected number, for example: 1234
    Dim nr As String =a       ' when i use this , then http request is not NOT FUNCTIONED
     ' Dim nr As String ="1234"  ' but when I use this row (declaration), then http request is FUNCTIONED perfectly
    HttpJob.Initialize("x")
    Dim string() As Byte ="http://www.abc.com/go.php?a="
    string=JoinBytes(Array(string,nr.getbytes))           'NOT FUNCTIONED with Dim nr As String =a
    'string=JoinBytes(Array(string,nr))                         'NOT FUNCTIONED with Dim nr As String =a
    log(string)    ' here I see "http://www.abc.com/go.php?a=1234"  which is functioned in explorer, but it is not functioned in ESP (wth declaration: Dim nr As String =a)
    HttpJob.AddHeader("Content-Type", "application/x-www-form-urlencoded")
    HttpJob.Post(string,"")
End Sub

    If Job.JobName="x" Then
        If Job.Success Then
                Log("OK")
            Else
                Log("NOK")
                 Log("ErrorMessage: ", Job.ErrorMessage)
                 Log("Status: ", Job.Status)
                 Log(Job.Response)   
        End If
    End If