Problems with preupgrade

[shmuel siegel <fedora shmuelhome mine nu>]

I tried to run preupgrade to update my fc10 x86_64 system to rawhide. 
The process successfully downloaded 1.8 G of updates but the anaconda 
install failed. Among other symptoms it says that turnOnSwap was called 
from upgrade.py line 313 with 1 non-keyword argument but needs 2
What is more confusing is that it said that it was installing fc9 
modules and updating fc10 modules even though nearly everything in 
/var/cache/yum/preupgrade/packages is fc11.