Problem with "FindAllChildren"

You dont't need to convert the below to array.

mainMenu.FindAllChildren("ObjectType","link", 50, true);

When you use FindAllChildren by default it will return as a Array.

FYI.

• FindAllChildren Method (Common for All Test Objects)
  Declaration

  TestObj.FindAllChildren(PropNames, PropValues, Depth, Refresh)

  TestObj	A variable, parameter or expression that specifies a reference to one of the objects listed in the Applies To section
  PropNames	[in]	Required	Variant
  PropValues	[in]	Required	Variant
  Depth	[in]	Optional	Integer	Default value: 1
  Refresh	[in]	Optional	Boolean	Default value: True
  Result	An array of the tested objects.

Once you got the list of menus available from the Pane to menuChild object.

You can script something like below.

var menuChild = mainMenu.FindAllChildren("ObjectType","link", 50, true);

// Log the search results
if (menuChild.length > 0)
{
for (i = 0; i < menuChild.length; i++)
//For clicking 
menuChild[i].Click();

//You can do your stuffs

}
else
Log.Warning("No menu items found.");