Alright a couple of things for you here. It looks to me that by your current settings your memory is running at around 272MHz (x2 is so it's actually 544, from 400), that being said I'm not surprised that you are having issues.
You have a couple of paths you can take here, first and probably easiest you can change the divider on your memory to something like 166 or 150, that will allow your memory to run much slower in relation to your FSB speed hopefully eliminating your problems and allowing you to continue to push the cpu if you can. The second path would be to loosen your memory timings and the third option is to add voltage to your memory.
DFI has exhaustive lists of options for memory setting on their lanparty offerings so don't feel bad that you are bit lost. I don't claim at all to have mastered memory overclocking, it can be a very tedious and time consuming process but I am continuing to learn as we all are. If you haven't already I would HIGHLY recommend that you read the guide to A64 overclocking in my sig, it is even written almost specifically for DFI boards so it will be a really big help you to if you give it a read or 10.
Give that a look and then come back with questions.
About reading CPU temps accurately there are a number of programs you can use that will work just fine for you. Try the ITE Smart Gaurdian that comes on your motherboard drivers cd or you can download it from DFI's website, motherboard monitor would work, even speedfan but for sake of simplicity go with the Smart Gaurdian.
One more thing and I'll let you tinker around some more with the system. I am a big DFI fan and swear I'll never buy anything else, that being said I would love to help you get the most from this sweet setup you've got so if you ever have an issue or anything feel free to PM me and I'll do all I can to help you figure it out.
Whew! Now go OC!