Not able to configure my domain for mail (MX Records)

[Hafizca]

i want to use google's mail interface with my site...they say to configure the mx records with following values...
Address Pref
ASPMX.L.GOOGLE.COM. 10
ALT1.ASPMX.L.GOOGLE.COM. 20
ALT2.ASPMX.L.GOOGLE.COM. 30
ASPMX2.GOOGLEMAIL.COM. 40
ASPMX3.GOOGLEMAIL.COM. 50
ASPMX4.GOOGLEMAIL.COM. 60
ASPMX5.GOOGLEMAIL.COM. 70

But im not able to do it.....
when i save it after entering these values the page returns to previous one......
pleeesss helpppppp