As far as I can tell the critical thing is an RPC error. I trimmed quite a lot – I am not sure how informative this all is. I meantime also sent a tcpdump and sysdiagnose output to Apple via bug reporter so let’s see if they come up with something.
D [15/Oct/2014:11:39:44 +0200] [Job 21] 3 filters for job:
D [15/Oct/2014:11:39:44 +0200] [Job 21] cgpdftops (application/pdf to application/postscript, cost 25)
D [15/Oct/2014:11:39:44 +0200] [Job 21] pstops (application/postscript to application/vnd.cups-postscript, cost 66)
D [15/Oct/2014:11:39:44 +0200] [Job 21] /Library/Printers/hp/filter/hpPostProcessing.bundle/Contents/MacOS/hpPostProces sing (application/vnd.cups-postscript to printer/StaffMinor, cost 0)
D [15/Oct/2014:11:39:44 +0200] [Job 21] argv[6]="/private/var/spool/cups/d00021-001"
D [15/Oct/2014:11:39:44 +0200] [Job 21] envp[12]="SOFTWARE=CUPS/1.7.2"
D [15/Oct/2014:11:39:44 +0200] [Job 21] Looking up "print.ict.ru.ac.za"...
D [15/Oct/2014:11:39:44 +0200] [Job 21] STATE: -connecting-to-device
D [15/Oct/2014:11:39:44 +0200] [Job 21] Connected to printer...
D [15/Oct/2014:11:39:44 +0200] [Job 21] Set job-printer-state-message to "Connected to printer...", current level=INFO
D [15/Oct/2014:11:39:44 +0200] [Job 21] job id is 30...
D [15/Oct/2014:11:39:44 +0200] [Job 21] Sending print data...
D [15/Oct/2014:11:39:44 +0200] [Job 21] Set job-printer-state-message to "Sending print data...", current level=INFO
D [15/Oct/2014:11:39:44 +0200] [Job 21] cgpdftops - using PPD file "/private/etc/cups/ppd/StaffMinor.ppd"...
D [15/Oct/2014:11:39:44 +0200] [Job 21] PS Matching Mode = AP_ApplicationColorMatching
D [15/Oct/2014:11:39:44 +0200] [Job 21] cgpdftops - languageLevel = 3, mediaBox.size.width = 595, mediaBox.size.height = 842
D [15/Oct/2014:11:39:44 +0200] [Job 21] cgpdftops - documentMediaBox.size.width = 595, documentMediaBox.size.height = 842
D [15/Oct/2014:11:39:44 +0200] [Job 21] Page = 595x842; 12,12 to 583,830
D [15/Oct/2014:11:39:44 +0200] [Job 21] slow_collate=0, slow_duplex=0, slow_order=0
D [15/Oct/2014:11:39:44 +0200] [Job 21] Before copy_comments - %!PS-Adobe-3.0
D [15/Oct/2014:11:39:44 +0200] [Job 21] %!PS-Adobe-3.0
D [15/Oct/2014:11:39:44 +0200] [Job 21] PID 38050 (/usr/libexec/cups/filter/cgpdftops) exited with no errors.
D [15/Oct/2014:11:39:44 +0200] [Job 21] Wrote 4 pages...
D [15/Oct/2014:11:39:44 +0200] [Job 21] Calling processor PageCounting before line %%Page: 4 4
D [15/Oct/2014:11:39:44 +0200] [Job 21] PID 38051 (/usr/libexec/cups/filter/pstops) exited with no errors.
D [15/Oct/2014:11:39:44 +0200] [Job 21] Calling processor PageScanning before line %%Trailer
D [15/Oct/2014:11:39:44 +0200] [Job 21] Final number of pages = 4
D [15/Oct/2014:11:39:44 +0200] [Job 21] Pages per copy = 4
D [15/Oct/2014:11:39:44 +0200] [Job 21] Allowing document iterator to handle job termination...
D [15/Oct/2014:11:39:44 +0200] [Job 21] Pre-processing tasks
D [15/Oct/2014:11:39:44 +0200] [Job 21] Current page number is 4
D [15/Oct/2014:11:39:44 +0200] [Job 21] Calling processor PageAccounting after line %%Page: 4 4
D [15/Oct/2014:11:39:44 +0200] [Job 21] PAGE: 4 1
D [15/Oct/2014:11:39:44 +0200] [Job 21] rpc_write_printer: RPC error 0x16c9a036
D [15/Oct/2014:11:39:44 +0200] [Job 21] RpcWritePrinter error -1!
D [15/Oct/2014:11:39:44 +0200] [Job 21] Cleaning up printer-state-reasons...
D [15/Oct/2014:11:39:44 +0200] [Job 21] STATE: -apple-job-blocked,job-completed-successfully,job-canceled-at-device,processing -to-stop-point,apple-job-error,offline-report,media-needed-warning,paused-report ,job-completed-successfully,job-printing,apple-job-restart,job-incoming,apple-jo b-intervention,apple-printer-busy,door-open-warning,apple-printer-errorstate,app le-printer-warming-up,apple-printer-active,apple-printer-manual-feed,apple-print er-unavailable,marker-supply-empty-report,offline-report,output-area-full-report ,interpreter-resource-unavailable-warning,apple-printer-page-punt,media-jam-warn ing,media-empty-warning,media-jam-warning,paused-report,apple-printer-deleting,a pple-printer-lowpower,apple-printer-printing,apple-printer-processing,offline-re port,apple-printer-unknown,toner-low-report,apple-printer-intervention,apple-pri nter-waiting,apple-printer-warming-up
D [15/Oct/2014:11:39:44 +0200] [Job 21] Aborting print job
D [15/Oct/2014:11:39:44 +0200] [Job 21] rpc_abort_printer: RPC error 0x16c9a060
D [15/Oct/2014:11:39:44 +0200] [Job 21] rpc_close_printer: RPC error 0x16c9a060
D [15/Oct/2014:11:39:44 +0200] [Job 21] Ready to print.
D [15/Oct/2014:11:39:44 +0200] [Job 21] Set job-printer-state-message to "Ready to print.", current level=INFO
D [15/Oct/2014:11:39:44 +0200] [Job 21] smb backend (PID=38058) exited with no errors
D [15/Oct/2014:11:39:44 +0200] [Job 21] smb backend will exit with status 0
D [15/Oct/2014:11:39:44 +0200] [Job 21] PID 38052 (/Library/Printers/hp/filter/hpPostProcessing.bundle/Contents/MacOS/hpPostProce ssing) stopped with status 1.
D [15/Oct/2014:11:39:44 +0200] [Job 21] Hint: Try setting the LogLevel to "debug" to find out more.
D [15/Oct/2014:11:39:44 +0200] [Job 21] End of messages
D [15/Oct/2014:11:39:44 +0200] [Job 21] printer-state=3(idle)
D [15/Oct/2014:11:39:44 +0200] [Job 21] printer-state-message="Filter failed"
D [15/Oct/2014:11:39:44 +0200] [Job 21] printer-state-reasons=none
E [15/Oct/2014:11:44:45 +0200] [Job 21] Stopping unresponsive job.