I just upgraded my computer. Before I was having this once or twice a day, resulting in an inability to log back on due to previous server errors. I haven't had an issue since upgrading.

Went from 4gb DDR2 to 8gb DDR3 ram
2.4ghz Dual Core to 4.0ghz 8-Core
New motherboard
New Case

Not saying hardware is the issue exclusively, but the game appears to like my new hardware configuration for now. I just don't think the game is optimized well at all.