That would explain why cups now hangs on the plug. If they disabled the parallel printer module in the kernel but cups is still trying by default to load their LP_MODULE, well let the crying begin. That make perfect sense, because as part of the apt-get dist-upgrade the new 2.6.32-5-kirkwood was installed when my problem started.
Cups hanging during startup is one thing but crashing the whole system is another. I haven't really looked into this, nor do I have cups on my plug, but if a module crashes the kernel when loading, the module is seriously broken and either needs to be fixed or removed from the default configuration (which Martin just did).
Loading modules for non-existant hardware or trying to load a module that doesn't exist at all should only give you an error message, not crash anything.