Hi,
I've installed Kubuntu 12.4, with KDE 4.4.8 and Linux 3.2.0-27.43 running.
Every time I start Kubuntu the system notification tells me that an application has crashed. I get the following line in the detail-section of the notification:
plasma-desktop crashes with ValueError in parts(): content line could not be parsed into parts
Has anybody an idea?

Can you check in ~/.xsession-errors to see if there are meaningful errors there related to that? Also, what applets are you using? Does the behavior occur with a new user account?