e2540c rubbish print

[didi2005]

Early morning when customer switched ON the e2540c MFP, after certain period it will auto print rubbish copies...
Print log:

4130

root

Print

2012-06-05T12:14:09

Print

9

A4

4011

1

I've updated the firmwares from 3000 to 3111, Universal Printer to PS3, RAW port to LPR...
But same problem still occur...
Customer side only had 2 windows PC and 1 Macbook...
Any ideas what is going wrong?