Casper scripting problems with Defaults write.

Can someone is able to explain to me why this script works locally but when I try to run it from the Jamf server it does not fail but it does nothing. the echo give me the actual login user in the logs.

#!/bin/bash

currentuser=""
currentuser=`/bin/ls -la /dev/console | /usr/bin/cut -d " " -f 4`
echo $currentuser

defaults write /Users/$currentuser/Library/Preferences/com.apple.Safari ManagedPlugInPolicies ' "com.macromedia.Flash Player.plugin" =         {
            PlugInDisallowPromptBeforeUseDialog = 1;
            PlugInFirstVisitPolicy = PlugInPolicyAllowWithSecurityRestrictions;
            PlugInHostnamePolicies =             (
                                {
                    PlugInHostname = "www.adobe.com";
                    PlugInIsFreshlyExpired = 0;
                    PlugInPageURL = "http://www.adobe.com/uk/software/flash/about/";
                    PlugInPolicy = PlugInPolicyAllowWithSecurityRestrictions;
                    PlugInRunUnsandboxed = 1;
                }
            );
            PlugInRunUnsandboxedOnFirstVisit = 1;
        };
'
exit 0