Same problem here, after months of production, 2 days ago my SaveToPDF geoprocessig tool stops working.The output isn't particurarly helpful:
esriJobMessageTypeInformative: Submitted.
esriJobMessageTypeInformative: Executing...
esriJobMessageTypeInformative: Executing (SaveToPDF): SaveToPDF 717114.646155556 95713.1951004844 717241.146155556 95839.6951004844 21781 D:\gis\Layouts base.mxd 1000 true titolo C:\Users\ARCGIS~1\AppData\Local\Temp\gisweb_gpserver\j558cd0f1f68349e29b6935e3ec68e32d\scratch\Output.pdf "mappa catastale, particelle, copertura del suolo"
esriJobMessageTypeInformative: Start Time: Fri Apr 20 13:16:48 2012
esriJobMessageTypeInformative: Executing (SaveToPDF): SaveToPDF 717114.646155556 95713.1951004844 717241.146155556 95839.6951004844 21781 D:\gis\Layouts base.mxd 1000 true titolo C:\Users\ARCGIS~1\AppData\Local\Temp\gisweb_gpserver\j558cd0f1f68349e29b6935e3ec68e32d\scratch\Output.pdf "mappa catastale, particelle, copertura del suolo"
esriJobMessageTypeInformative: Start Time: Fri Apr 20 13:16:48 2012
esriJobMessageTypeInformative: Running script SaveToPDF...
esriJobMessageTypeInformative: Collecting input parameters
esriJobMessageTypeInformative: Processing Map Extent
esriJobMessageTypeInformative: Setting scale to: 1000.0
esriJobMessageTypeInformative: Saving as PDF
esriJobMessageTypeError: Failed.
esriJobMessageTypeError: Execution of job j558cd0f1f68349e29b6935e3ec68e32d failed because of crash or termination of the server object.
esriJobMessageTypeInformative: Completed script SaveToPDF...
esriJobMessageTypeInformative: Succeeded at Fri Apr 20 13:16:56 2012 (Elapsed Time: 8.00 seconds)
esriJobMessageTypeInformative: Succeeded at Fri Apr 20 13:16:56 2012 (Elapsed Time: 8.00 seconds)
Any ideas?