Can someone confirm/deny that this is normal please?

[jparman]

Shot this from my Oly E-420, which is about a year old. Under specific circumstances, especially low light, it is a noise monger. I shot this w/ the following settings

RAW format
Noise Reduction - OFF
WB - 5600K
ISO - 100
2 sec exposure @ f9.

What concerns me is the regular pattern of the noise (vertical striping). While images w/ better exposure don't initially appear to have the striping, upon closer inspection they all do (except when it comes to daylight shots.
Is this something that is "normal". If it is, then I'll try not to be as disappointed as I am right now.