You remember to lower the DRAM clock? If not that would be why it becomes unstable, as without lowering it the ram is running at the same speed as the CPU/FSB (1:1). Unless you have some really good PC3200, I doubt that it will run at 235. It doesn't show in the manual what options are available (frequency or divider), but lower the DRAM clock down to 133 or so. If it is dividers (1:1, 2:3, 5:4, etc), post what is available.
Also is that 2x2Gb or 4x1 GB sticks? If it is 4x1 make sure that the command rate (should happen by default, but still check) is set to 2T and not 1T. It is a design limitation on the memory controller when all ram slots are populated.
Edit: Couple of things I forgot,
1. Lower the HTT to 3. Try to keep it around 1000 or less; lower won't affect anything, but too high will definitely make it unstable.
2. DO NOT up the PCI-E speed, lock/leave it at 100 MHz.
here is a nifty little utility for playing around with the numbers without actually changing anything, A64Calc.rar - FileFront.com
With it here are your settings at stock speed,
and with the settings you used,
sorry to say but there is no way that it will run stable at all with those settings, not surprised you had trouble.
Try to keep the memory clock close to or under 200; better is to set it as low as it will go until you get the CPU as high as it will stably go, that way it takes the ram out of the picture (and don't forget to lower the HTT multi accordingly as well). Once you have found the max overclock on the CPU, then you can start raising the ram clock.