I am not going to look into the specifics of this problem
And won't bother trying to fix any of this,
but it seems like the recent update of the Zen Kernel or the udev module
have caused udev not to work properly in combination with the Zen-Kernel.
Other Kernels work fine and luckily I am able to change them easily but watch out if you have no fallbacks.
Again I am not trying to fix anything here or expect anything to change till next update.
Would you mind going into the specifics of this? I may be experiencing something similar and want to verify if this is the problem. How did you determine this?