Overclocking always involve much more than just a voltage bump and a FSB increase. It requires concentration and patience, to test out each possible FSB vs. clockspeed combination for an optimal higher clock.
The problem you suffered was probably due to a misaligned timing between the memory and the CPU.
So I would recommend you stick to the stock clock, and do a little more research on overclocking (FSB bump, voltage bump, NB voltage) before attemping another try. However, keep in mind that even the world's greatest overclocker went through the phase you just experienced.