kdebase-workspace from testing breaks plasma

[Jeff Anderson]

I've been following the 4.2 rc rpms from the kde-testing repo, and did a yum 
update on Saturday that updated a couple rpms.  In particular it updated me 
to kdebase-workspace-4.1.96-4.fc10.x86_64

Ever since then plasma refuses to start, failing at 
plasma: symbol lookup error: /usr/lib64/kde4/plasma_wallpaper_image.so: 
undefined symbol: 
_ZN6Plasma16PackageStructure21setAllowExternalPathsEb

I've tried the usual thing of removing plasmarc and plasma-appletsrc, but 
that doesn't solve the problem.

KDE does start, and I can start programs from the command line, including 
krunner.  But when I try to start plasma the panel flashes on, then quits, 
leaving the above message on konsole.

I've tried removing kdebase-workspace and reinstalling, but to no avail.  
Has anyone else tried this update?  Is it working for other people?

Jeff Anderson