Fernando,
a brief follow-up. Everything should now be working for you for the
SFR calculation if you update yt again. The fix for cylinder volume
calculation (my_disk.volume('mpc')) which the SFR module uses has been
made.
Let us know if you run into any problems.
--
Stephen Skory
s at skory.us
http://stephenskory.com/
510.621.3687 (google voice)