You might want to post that one in the Illustrator forum.
And we have found no similar errors from other customers, or with any of our PostScript printers.
Well I suppose I could post it there, but I wouldn't be hoping for any sort of response: there's not exactly much to read into. We've found that it's typically better to try and find a workaround for CS errors (in this case, copy/paste the contents of the open file into a new ai file, re-save with new filename) than to try to guess at the cause from these kinds of error messages, which are nearly useless.
That said, this one is a nagging annoyance for our designers, and given that we get the same behavior across multiple systems/OSs/printers, and that the error only occurs when printing from photoshop cs 5.1 (not when printing from illustrator, or Preview), the root cause MUST have something to do with photoshop. Perhaps there is just something about the particular files and their interaction with photoshop, but whatever the real reason, photoshop is playing a part.
And so, here we are. Perhaps there are other troubleshooting measures I've missed? Maybe there's some limitation with printing in Photoshop I'm not aware of? Maybe there's a setting somewhere in the print dialogue that we should enable/disable for further troubleshooting? I'm basically looking for other shot-in-the-dark types of things to try at this point; I harbor no illusions that there's anyone out there who knows what's happening or has seen this before.
With that in mind, fire away! I'm willing to try nearly anything.