"Failed to read side-channel request!"

[ja]

error log

D [03/Oct/2011:03:03:47 -0400] [Job 71] Gutenprint: Ending job
D [03/Oct/2011:03:03:47 -0400] [Job 71] Gutenprint: Printed total 150009 bytes
D [03/Oct/2011:03:03:47 -0400] [Job 71] Gutenprint: Used 3.130 seconds user, 0.180 seconds system, 13.849 seconds elapsed
D [03/Oct/2011:03:03:47 -0400] [Job 71] Read 2 bytes of print data...
D [03/Oct/2011:03:03:47 -0400] [Job 71] Wrote 2 bytes of print data...
W [03/Oct/2011:03:03:47 -0400] [Job 71] Failed to read side-channel request!
D [03/Oct/2011:03:03:47 -0400] [Job 71] Set job-printer-state-message to "Failed to read side-channel request!", current level=WARN

or

I [03/Oct/2011:03:03:47 -0400] [Job 71] Finished page 1...
D [03/Oct/2011:03:03:47 -0400] [Job 71] Set job-printer-state-message to "Finished page 1...", current level=INFO
D [03/Oct/2011:03:03:47 -0400] [Job 71] Read 2551 bytes of print data...
D [03/Oct/2011:03:03:47 -0400] [Job 71] Gutenprint: Done printing page 1
D [03/Oct/2011:03:03:47 -0400] [Job 71] Wrote 2551 bytes of print data...
......
......
[03/Oct/2011:03:03:47 -0400] [Job 71] Read 2 bytes of print data...
D [03/Oct/2011:03:03:47 -0400] [Job 71] Wrote 2 bytes of print data...
W [03/Oct/2011:03:03:47 -0400] [Job 71] Failed to read side-channel request!