As you have Acrobat installed, and the plufgin installed, you must configurate K-Meleon.
1) Look at Edit > Advanced Preferences (F2) > File Types, and change the action if .pdf is in the list. Take Default if you have already set Foxit Reader as default pdf reader (When launching it, it's set automatically), if not, you can 'Open with this application', and browse to set F
Forum:
Bugs