gconftool-2 --recursive-unset /system/osso/connectivity/IAP/z_fMMS-APN
that should remove the fmms one

as for your provider, as mentioned above, be careful you dont remove your default one. as long as you know its not it then...

if you run:
gconftool-2 -R /system/osso/connectivity/IAP

it should give a list of all the connections you have, whatever the path is to the provider one you don't want, add that to the first command i gave you