CMS,
PrintShop Mail takes all page size settings, paper handling and other features from the driver used, unlike many other applications, which is why it may be a little more prone to crash if the driver isn't compatible.
I would suggest you try getting a different driver, perhaps one specifically made for the Canon IR125VP instead of using a 110 or 150 driver. Try a PostScript driver first, but if it doesn't work, feel free to try a PCL driver as well.
If you have Acrobat, do you get the same kind of crashes if you use the Adobe PDF driver? If not, a potential workaround could be to print to a pdf file, and then print the pdf from Acrobat.
Regards,
Raphaël Lalonde Lefebvre