I googled "husqvarna iris manual" there were several online sites with free downloads, you might want to try a different site if the one you got wasn't good quality.
I found this one on line for $$:
http://www.sew4less.com/product/4343/Viking_Iris_Instruction_Manual
And finally, I would contact a Viking dealer, I'm pretty sure they can order manuals for older models.