Russell,

Another suggestion would be to use a simple vbScript.

for example:

myCopy.vbs

SourceFile = WScript.Arguments(0)
TargetFile = WScript.Arguments(1)
SET oFSO = Createobject("Scripting.FileSystemObject")
oFSO.CopyFile SourceFile, TargetFile

Or:

SET oFSO = Createobject("Scripting.FileSystemObject")
oFSO.CopyFile WScript.Arguments(0), WScript.Arguments(1)

[Update] Sorry I forgot to launch InstallShield

SET oShell = Createobject("WScript.Shell")
oShell.Run("""C:\Program Files\InstallShield\Express 5.0 Fox Pro\ISIDE.EXE""")

[Update 2] Ooops. You do not need to run ISIDE, but your installation program, but it would be similar to launching ISIDE or any other exe.