Original iMac Networking

I hope I found the right spot for this post. Couldn't find a prehistoric section.

Well it finally happened; the original iMac (i think it has been nicknamed the Blueberry) my mother has been using primarily as a word processor has reached the point of forced hibernation. She is using a Macbook Pro she just purchased last year and is trying to pull her documents off of the iMac. I tried using a thumb drive, and a power external hard drive, but they both pulled up an error message that reads, "The software needed to use the USB device 'USB to Serial-ATA bridge' cannot be found. Please refer to the device documentation to install the necessary software." I don't really think installing any software on this thing is an option, so I tried my hand at networking the two via ethernet. I have not been able to reach a proper connection between the two, and have been trying to use walkthroughs posted on apple's website to get a connection. I made sure to turn on the file sharing on the iMac, and I still can't get the computer to register on the MacBook Pro's network. Does anyone have any experience with this? Any other recommendations? Here are the specs of the iMac (don't laugh!)

Mac OS 8.6
Built-in Memory 32MB
Virtual Memory 400 MB
Largest Unused Block 384.8 MB

And the Macbook Pro (for what it's worth)
Mac OS X 10.6.8
Processor 2.3 GHz Intel Core i5
Memory 4 GB 1333 MHz DDR3

Thank you so much in advance!