I posted a question. I then solved my problem myself. There haven't been any acceptable (true) answers posted to my question. What should I do now? Should the question be closed?
No, you should post your solution as an answer and then after 48 hours accept it. (I think the limit is 48 hours from when you posted your question).
Please see this blog post from Jeff on Accept your own answers.
This is an interesting quote from one of Jeffs posts:
I encourage you to leave your own answer on your own question, of course. But I’d also encourage you to go out of your way to find the greatness in another programmer’s answer to your question — even if you think you’ve already found the right one.