Tkinter.Button error

[ABC]

I have two frames
top frame and bottom frame.
In the top frame I implemented a group.
Now, when I try to add Tkinter.Buttomn widget in the group in the top
frame it gives error . Can anyone help me and tell me what the error is?

Here is the code

frame1=Frame(master, relief=sunken', borderwidth='2')
frame2=Frame(master, relief='sunken', borderwidth='1')

frame1.place(relx=0, rely=0, relwidth=1, relheight=0.50)
frame2.place(relx=0. rely=0.50, relwidth=1, relheight=0.50)

group1=Pmw.Group(frame1, tag_text="Hello")
group1.pack(fill='both')

button=Tkinter.Button(group1.interior(), text='8.00')
button.pack()

The above program gives an error in TKinter in the second last line.
I have no clue of what the error is? Can anyone help me?
Need futher information, please let me know.