It's all in the links pointing at each individual page. The post pages have higher PR links pointing at them.

Backlinks from high page rank sites will increase your page rank. No matter you are doing forums posting , blog commenting, social book marking.

Another thought is to have a link going back to the homepage of your site from the posts that are a higher page rank. In theory it could pass page rank back to the main url.

Of course be sure to give a good reason to get back to the main page i.e. be sure to go to home page to sign up for my power-packed free newsletter......

There is no need to 'fix it'. PR is very misunderstood. You can have a PR of zero and be out ranking a site with a PR of 5 etc. It has little to nothing to do with ranking.

Try to build a backlinks on that page to rank higher in search engine.

Though you have some links of PR 2-3 sites, your page rank not upgraded, you should use some higher PR backlinks and by the way Google needs little time to show you the result. So, keep building links until the second page rank update.

I have the exact same thing with one of my own sites. I don't get why it happened though, because I built 90% of my links to the website's homepage... But, who's going to complain about getting higher PR on some of the inner pages?

interesting. dont think ive seen that ever before. You must have some popular articles being linked to

That is NORMAL. That because you have more backlinks pointing to your posts. If you want to rank you home page, you can internal linking your high PR post to your home page. So the PR from your posts will pass some PR to your homepage. Just do it naturally.

Yes i too have like this PR higher in inner pages. It happened inner pages get more back links while compare homepage