Jarin,
I cannot specifically answer why your site's PR is not available. There are numerous possibilities including a glitch in the latest data feed which offers PR. I was able to verify using a couple tools the PR for your website is not available.
I understand your concern. Penalized websites will show the same results you are seeing, a PR of n/a or a grey bar. Since you are ranking #1 for numerous keywords it seems clear you are not penalized.
I do not look at the PR for any of my sites. It has no tangible value. You can choose to agree or disagree, but I have worked with many sites and helped them earn top rankings without looking at PR at all. If you don't wish to take my advice, perhaps you will accept the same advice directly from Google.
In 2009, Google discontinued the practice of updated PR and now they only offer the information about 3-4 times per year. Susan Moskwa from Google wrote:
"the PR you see publicly is different from the number our algorithm actually uses for ranking. Why bother with a number that’s at best three steps removed from your actual goal, when you could instead directly measure what you want to achieve? "
For further details read the full article: http://googlewebmastercentral.blogspot.com/2011/06/beyond-pagerank-graduating-to.html
