Some Site Admin -> Options not working

Hi,
I have a new wpmu1.3 installation and I noticed that some Site Admin -> Options are not working. In more detail:

- no mail is send to admin on new user/blog registration (it seems that get_site_option( "admin_email" ); is not working;
- if I change the welcome mail text the mail sended to users contains the old text;

I solved manually modifying the code of wpmu-function.php around line 1400. There is a way to avoid this?
Thanks
dat