Writers, being at times temperamental creatures, may be particularly prone to frustration, which doesn't help the situation. I'm also very good at avoiding things I find uncomfortable, frustrating, or maddening, and my procrastination skills are honed to a sharp edge. But I think that might be a requirement for authors. Either way, the longer you practice avoidance and the more non-writing work you do to fill your time, the worse the block will get.
I'm just emerging from my own bout of writer's block. I'd say I've been suffering for a month, but deep down inside, I know it's longer than that. Because writer's block isn't just about the inability to put words on paper. There's nothing stopping anybody from writing at any time, and "I have writer's block" is a weak excuse for not getting work done. Writer's block is a deeper sense of dread, a brush with an alternative life where you're no writer, and it's usually self-imposed. It's not something that happens to you, it's an obstacle you've built yourself, consciously or unconsciously.
We plan to have some good discussions about and suggestions for overcoming writer's block this week, and hopefully it'll be enough to get some people inspired.