The Plugin Firewall whitelist rule you would add to the Plugin Firewall Whitelist Text area is /fv-wordpress-flowplayer/flowplayer/(.*).swf, click the Save Whitelist Options button and activate the Plugin Firewall again.
Also check all of your Plugin Firewall whitelist rules. If there is even 1 mistake in the format of the whitelist rules it will negate all the whitelist rules. Whitelist rules are separated by a comma and a space between each rule.
Example Correct format: /plugin-folder-name1/plugin-script-name1.js, /plugin-folder-name2/plugin-script-name2.js, /plugin-folder-name3/plugin-script-name3.js