PRB: The Internet Transfer Control Causes "Invalid Callee" Error

When using the Internet Transfer ActiveX control in Visual FoxPro 5.0, the error "Invalid Callee" occurs when issuing the control's Execute command. This error occurs if the control is either used on a form inside of Visual FoxPro or run in a distributed executable.

Placing the SYS(2333,0) function in the Load event of the form eliminates the error.

Sometimes an ActiveX control may register itself incorrectly as supporting a dual interface: a combination of IDispatch and Vtable binding. When this occurs, Visual FoxPro has the capability to turn off the dual interface support using the SYS(2333), ActiveX Dual Interface Support, function.

Steps to Reproduce Behavior

1. Create a form called Transfer.scx.
2. From the Form Controls toolbar, click the OLE Container control.
3. After clicking on the form, select the "Insert Control" radio button located in the Insert Object dialog box.
4. Select the Microsoft Internet Transfer control from the list box.
5. Place a command button on the form and place the following code in the Click event:

         THISFORM.OLECONTROL1.EXECUTE("ftp://host.com/pub")
   							

6. Run the form and click on the command button. Note that the "Invalid Callee" error occurs. Place the "=SYS(2333,0)" statement in the Load event of the form and note that the error does not occur.

For more information about ActiveX controls and dual interface, please see the following article in the Microsoft Knowledge Base: