Thunking Spooler APIS from 32 to 64 Process has stopped working

What exactly would be causing this error.

Thunking Spooler APIS from 32 to 64 Process has stopped working

Details:
Problem signature:
Problem Event Name: APPCRASH
Application Name: splwow64.exe
Application Version: 6.0.6001.18000
Application Timestamp: 4791a2b0
Fault Module Name: hpzuilhn.dll
Fault Module Version: 61.53.25.9
Fault Module Timestamp: 4791ad6d
Exception Code: c0000005
Exception Offset: 00000000000d89c4
OS Version: 6.0.6002.2.2.0.768.3
Locale ID: 1033
Additional Information 1: 18bd
Additional Information 2: e4509782aa776950d09270b30152093b
Additional Information 3: 2d37
Additional Information 4: 873289f837e39d53356e2992406cd5dd


-------------------------------------------

This occurs when trying to use Canon's Easy PhotoPrint EX software with my new Canon MX860 Printer, connected over a LAN. The software and the printer drivers are all up to date. This only occurs on my Vista 64 machine. My Win XP machine has no trouble running the software.