What exeterdad is saying is that your $BROWSER variable might not be set to firefox, and that something might have gone wrong with your editing of .bashrc
I think the browser_vl command in the launcher of the docs calls browser, which in turn depends on the $BROWSER variable. Don't ask me why.
You can see what the $BROWSER variable is currently set to by doing:
If it still says seamonkey, open up a console and do:
It should then be set for firefox, BUT it won't be applied to another console or survive reboots... that's why it needs to go in the .bashrc (or /etc/profile if you want to apply it to all users).
If the line that does the export BROWSER command to firefox in uncommented, and the other export $BROWSER lines are commented, then it should work and if it doesn't, I'll be puzzled.
Of course, you can always edit the launcher like overthere said and put the firefox command there directly, instead of browser. But a more robust solution is fixing the $BROWSER variable. Or even get rid of the icon and bookmark the file in firefox.
Now that I think about it, It might be an idea to develop a vector utility to change the $BROWSER variable in .bashrc or /etc/profile.
Hope this helps.