>Introduction:
>I have an ActiveX (moca.ocx) from a software development kit
>(Melita OpenClient Access). Melita is a server (dialer system) used by call centers. In the package some samples are included for Visual Basic, Visual C++ and Java. Also, on the cover page of documentation appears the names of Delphi and Powerbuilder.
>
>Question:
>In the Project/Components window of Visual Basic, the control appears under the name of "MOCA OLE control module". But in the Tools/Options/Controls window
>of Visual FoxPro (option ActiveX controls) the moca.ocx does not appear and I cannot add it. Finally, my question is: "Is any ActiveX should works on both (VB and VFP)?".

Try by adding an OLE container to a form and selecting "insert control" and see if it appears there. The other option is trying to use it programmatically on a form class like so:

Define Class myOLETest As Form
  Name = "frmRS"
  Height = 300
  Width = 500
  Autocenter = .T.
  Add Object "Moca1" As MocaControl With ;
    Visible = .T.
EndDefine

Define Class MocaControl as OLEControl
  OLEClass = "MocaProgrammaticName.Control.1"
EndDefine

Although to answer your last question not all activeX controls work in VFP for the simple reason that most are not designed with VFP support in mind. You might want to contact the vendor and ask them if it supports VFP. Most likely they will say it does not or that it wasn't tested.

PS
Is this really a VFP question?