Some people have had difficulties in leaving comments on my blog lately so I thought I'd investigate. Tonight I wanted to respond to two comments left today so using a borrowed laptop from school, I posted the first comment without any problems, adding my details in the required fields. Then when I went to the second comment, I noticed that my blog was telling me I was already logged in with an option to change user. After the comment was rejected the first time, I thought I'd try the option. Clicking on that link however was useless, taking me to an Error page.
I figured that maybe the problem lies in how Firefox uses my Private Data. So after a bit of trial and error, I went to Tools, then Clear Private Data, ticked the Cookies and Cache options and then Clear Private Data Now button. I navigated back to the blog and success - the comment field boxes were clear ready to use.
Failing that, click Back, then copy your comment, dump it in an e-mail and I'll drop it in myself. E-mail address over in the right hand sidebar under Feeds & Links. Hope this helps.