http://plugindoc.mozdev.org/faqs/firefox-linux.html
So it is wherever you installed it/plugins, and ~/.phoenix/plugins, like I said. Make sure you have both the .so and the .xpt. You may need whatever the mandrake version of compat-glibc is (it may very well have the same name). It may have a menu item, like Help/About Plugins, which will tell you what plugins it detects.
-Eric Hattemer
