Well, I’ve found the offending php file. It’s called “click-tracker.php”
The author is Eric Lamb (email : [email protected])
I’ve sent him an e-mail asking him to change the language in the next release. However, in the mean time you can modify the file yourself in Notepad or similar. Open the file and scroll down until you find the above line and just substitute the wording to maybe ‘Firefox 3 is wrong…’. Don’t forget to save it as click-tracker.php and then FTP it to it’s home directory.
In my case this was: /….(your home directory)…/wp-content/plugins/wp-click-track
I hope this will be helpful to someone.