How to group rectangle and textFrames

Hi all,

I am trying To group one rectangle And textframe In Indesign Server And executing the below code:

Dim mygroup As InDesignServer.Group
Dim gparray(1)
gparray.SetValue(CaptionFrame, 0)
gparray.SetValue(rect, 1)
mygroup = IndDoc.Groups.Add(CType(gparray, InDesignServer.Objects))

Above line throwing the following exception
'Unable to cast object of type 'System.Object[]' to type 'InDesignServer.Objects'.

Regards,

Suresh