Unknown error 009-391

After replacing a cyan toner and a waste toner cartridge on a Xerox WorkCentre 7345, i tried to print a full printer report, but the printer hung. after rebooting it said the cyan toner and waste cartridge were still at 0%. i rebooted the particular machine several times until it returned an error code: 009-391. i looked up this code, but this even seems to be unknown to the xerox databases. after rebooting several more times, the error was gone and the cartridges got recognised. a job that normally takes 2 mins, took me almost 45 frustrating minutes. please, what does the error code mean and what can i do to avoid such situations, other than proper prcedure following? thanks in advance for your cooperation. kind regards, Hans a support engineer from belgium