Yuk – Switched to Fedora 11 recently – ran into problems today installing updates …

http://mirror.its.uidaho.edu/pub/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.lib.ucdavis.edu/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.cc.vt.edu/pub/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.anl.gov/pub/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
http://mirror.uoregon.edu/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.

ftp://mirror.cs.princeton.edu/pub/mirrors/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 4] IOError: [Errno ftp error] 421 Sorry, mirror already has 21 users logged on.  Try again in 10 minutes.
Trying other mirror.
http://mirror.unl.edu/fedora/linux/updates/11/i386/grubby-6.0.87-1.fc11.i586.rpm: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.

seems to be a common thing according to the fedora forums.

found an alternate source for theses Updates :

rpm -Uvh http://kojipkgs.fedoraproject.org/packages/mkinitrd/6.0.87/1.fc11/i586/grubby-6.0.87-1.fc11.i586.rpm http://kojipkgs.fedoraproject.org/packages/mkinitrd/6.0.87/1.fc11/i586/libbdevid-python-6.0.87-1.fc11.i586.rpm http://kojipkgs.fedoraproject.org/packages/mkinitrd/6.0.87/1.fc11/i586/mkinitrd-6.0.87-1.fc11.i586.rpm http://kojipkgs.fedoraproject.org/packages/mkinitrd/6.0.87/1.fc11/i586/nash-6.0.87-1.fc11.i586.rpm  http://kojipkgs.fedoraproject.org/packages/gdb/6.8.50.20090302/33.fc11/i586/gdb-6.8.50.20090302-33.fc11.i586.rpm