The cupsys version is of course 1.2.1-4 and not 1.2.4. udev version is 0.093-1 kernel is 2.6.17.6
I looked a bit closer at the behaviour today. When I switch on the printer, usblp module is loaded and the device /dev/usb/lp0 is created with access rights drw-rw---- root lp. When I print a test page from the cupsys admin webpage on hp:/usb/hp_color_LaserJet_2550_series?serial=00CNFDD05275, I get "open print channel failed" and /dev/usb/lp0 vanishes immediately.
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