Are you sure you are using the latest build of the blog? it works fine on my site and thats on trunk - defaults without any mods.. So it might have already been fixed or you have changed something to break it.
You can see a list of issues on trac at - http://open.silverstripe.com/report
If its not already a issue then feel free to add it to it. If you can work out why its not working and submit a patch we would be more then happy to merge it back into the blog module.
Using SS-v2.2.1 and blog-v0.1 and I have the issue independent of browser IE/FireFox.
Since I'm a "complete beginner" I have't changed or modified anything. Should I upgrade blog from v0.1 to latest v0.1?
Feel free to check it out at http://www.brfskraddaren.se/blog