Socket: Failed to read side-channel request (2)

[Thomas Küstermann]

The missing part of: http://www.cups.org/newsgroups.php?gcups.general+v:32307

<log>
INFO: Attempting to connect to host <printer> on port 9100
STATE: +connecting-to-device
STATE: -connecting-to-device
INFO: Connected to <printer>...
DEBUG: Connected to <printer>:9100 (IPv4)...
PAGE: 1 1
DEBUG: backendRunLoop(print_fd=3, device_fd=4, use_bc=1, side_cb=0x401862)
INFO: Printer is now on-line.
DEBUG: Read 8192 bytes of print data...
DEBUG: Wrote 8192 bytes of print data...
...
WARNING: Failed to read side-channel request!
// some time later :
DEBUG: Read 8192 bytes of print data...
DEBUG: Wrote 8192 bytes of print data...
...
INFO: Sent print file, 5160398 bytes...
INFO: Print file sent, waiting for printer to finish...
INFO: Ready to print.
</log>

The problem is reproducible, but it seems to NOT depend on:
- document size
- number of pages

What I can say about the documents:
- they seem to be complete (correct head and tail)
- they can be re, or maybe to resolve? Thanks in advance for each hint.
ndered completely with ghostview ('gv <file>')

If I try to print the document on the old cups, it succeeds. PPD files are the same and original ones from HP.

What maybe the next steps to find the reason for problem
- Thomas