It was an earlier thread with this subject but no conclusion was made.
I have the same problem with the same software, OES SP1a and iPrint
Client 4.11. For some reason the print spooler is crashing and no more
printers are available. Generaly, a workstation reboot brings back the
printers but only until the next crash. We can't tide the problem to some
specific printer driver, OS version, SP version or anything else. And we
have a couple of dozens of workstations with this problem.

Is someone who know the solution to this issue ?