Here's what I wrote after succeeding with Take5:
You do NOT need root access to flash Take5 or 1.6 stock. Odin does it all. So here's some more detail about how I finally got it done (thanks to everyone helping):
1. Download
http://www.junefabrics.com/bin2/SamsungUsbBehold.zip and unzip the files, then run the "Setup.exe" file. Your phone does NOT need to be connected to the computer to install this driver.
2. Download Odin at
4shared.com - free file sharing and storage. This file includes other files but you need ONLY the "Odin Multi Downloader v4.03.exe" file (there may be another download location for it). So unzip this folder and put Odin somewhere on your PC so it's handy. Don't need to open it yet, though.
3. Download Take5 from
4shared.com - free file sharing and storage. Unzip this folder that contains two files: "Behold2_partition.ops" and "BH_MAN_Take5.tar.md5".
4. Open "Odin Multi Downloader v4.03.exe" and then:
a. Click the "OPS" button and select the "Behold2_partition.ops" file
b. Click the "PDA" button and select the "BH_MAN_Take5.tar.md5" file (you may get a message saying "Image Image Type" but you can ignore it)
5. While your phone is still not connected to the computer, turn the phone off. Then you need to get into DOWNLOAD MODE. To do this, hold down (in order, and you KEEP HOLDING THEM) Volume Down, Center D-Pad Button (the round one), and then End Call. Remember: KEEP HOLDING THEM ALL DOWN THE ENTIRE TIME. The phone will turn on, and should say that it's in Download Mode (psz clarified this). It will take several seconds. Don't let go of any of the three buttons until you see "download mode".
6. Now that the phone is in download mode, connect it to the computer's USB port. When I did this, Windows asked me if I wanted to install drivers, so I said yes and let it do it's thing.
7. In the Message box in the bottom-left corner of Odin, it will say something about your phone being connected. Now you click the Start button in Odin. Wait maybe a few minutes and your phone will reboot and turn on with Take5 running.
8. Unplug phone from USB and enjoy.