Migration assistant can't find my new macbook pro

I have been using a Macbook for the past three years and it is currently running OS 10.5.8. Today I purchased a Macbook Pro, and tried to migrate my data using the migration assistant and connecting my two laptops via an ethernet cable. My Macbook Pro found my old computer with no problem and provided the numerical code I will need to input into my old computer, but my Macbook couldn't locate my new computer. I downloaded the migrationDVD/CD sharing update to my old computer as per the instructions on the website, only to get the message on my computer that I cannot install it, because I'm already running a newer version than what's listed on the website. Is there a way to troubleshoot this so that my old computer can find my new computer? I do not have access to wireless networks, firewire, etc - so the only way for me to do this is to use my ethernet cord. Thanks.