Why do you wanna do both? I'm not sure, I've only done one of each. Applying online is cheaper (no need to waste paper & mail them) and faster. Sending in two applications might just confuse CIC...what would most likely happen is that they'll ignore the paper one.
They track your work permit application through your UCI, so if they see you have a current application open they won't work on the second one. This happened to me, my husband applied for my open work permit and a month later I applied for my closed work permit just to be sure. They ignored the second application and refunded me the fees that I paid for it since they have approved the first one already.
