I save a new bookmark on my bookmark toolbar, if I go to click on the new bookmark it will take me to a completely different site, sometimes ones I've never visited.
I have items on my bookmark tool bar that I have saved within the last year. Recently whenever I try to make a new one, it won't work and will send me to a different website. If I try and edit the bookmark and save the changes, it will just change it back to a different website no matter how many times I try and change it.
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:184.108.40.206) Gecko/2010031218 Firefox/3.0.19
First of all, and although possibly not related to your problem, I will remind you that the version of Firefox you are using at the moment as been discontinued and is no longer supported. Furthermore, it has known bugs and security problems. I urge you to update to the latest version of Firefox, for maximum stability, performance, security and usability. You can get it for free, as always, at www.getfirefox.com.
As for your problem, you may be having a problem with some extension or plugin that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?