I had this problem a couple times on my Vista64 system just after I installed an Epson 9880, don't know if the printer had anything to do with it. The problem seemed to be assocaited with a couple specific files only, not every file.
Did you recently retire and old printer? One theory is that every problem file had previously been printed on a 7800 which was no longer installed on the system, perhaps some piece of software was mourning it's missing first-true-love printer.
The easy fix was to select a different printer as the default printer in the control panel (say my office printer), then just choose the 9880 from the CS4 print dialogue. Another fix I got off the net was to open the file in CS3, then save it, that would "fix" a file that persistently couldn't find a printer. Another fix was to save the file as a .tif, then load & print that.
Fortunately have not a recurrence since I upgraded to CS4 11.0.1, 64 bit version.