Try enabling debug in /etc/syslog.conf
restart syslogd
try to install plugin again
see if anything useful is shown in /var/log/debug.log
Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:132] Executing: /bin/rm -rf /var/tmp/firmware Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:146] Executed: /bin/rm -rf /var/tmp/firmware Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:132] Executing: /bin/mkdir -p /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:146] Executed: /bin/mkdir -p /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:132] Executing: /usr/sbin/chown www:www /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:146] Executed: /usr/sbin/chown www:www /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:132] Executing: /bin/chmod 755 /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:146] Executed: /bin/chmod 755 /mnt/RaidVol/software/.freenas Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:132] Executing: /bin/ln -s /mnt/RaidVol/software/.freenas /var/tmp/firmware Oct 10 02:07:39 MyServer manage.py: [middleware.notifier:146] Executed: /bin/ln -s /mnt/RaidVol/software/.freenas /var/tmp/firmware Oct 10 02:07:46 MyServer manage.py: [middleware.notifier:149] Executing: jls -j 1 Oct 10 02:07:46 MyServer manage.py: [middleware.notifier:163] Executed: jls -j 1; returned 0 Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model bsdGroupMembership from app account blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Advanced from app system blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Email from app system blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model SSL from app system blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Settings from app system blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Alias from app network blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model LAGGInterface from app network blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model LAGGInterfaceMembers from app network blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Disk from app storage blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model MountPoint from app storage blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model ReplRemote from app storage blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model Volume from app storage blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model RPCToken from app services blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model iSCSITargetPortalIP from app services blacklisted, skipping Oct 10 02:07:46 MyServer manage.py: [freeadmin.navtree:257] Model services from app services blacklisted, skipping Oct 10 02:08:02 MyServer autosnap.py: [tools.autosnap:109] Checking if process 3959 is still alive Oct 10 02:08:02 MyServer autosnap.py: [tools.autosnap:116] Process 3959 gone
2012/10/10 13:57:08 [crit] 2462#0: *396 open() "/var/tmp/firmware/0000000002" failed (13: Permission denied), client: 192.168.0.130, server: localhost, request: "POST /plugins/plugin/install/?iframe=true&X-Progress-ID=78c0baf8-1ef5-4a8f-85af-15eae0f7ea51 HTTP/1.1", host: "192.168.0.180", referrer: "http://192.168.0.180/"
# ls -l /mnt/RaidVol/software total 184465 drwxr-xr-x 2 www www 2 Oct 9 23:27 .freenas drwxr-xr-x 2 root wheel 2 Oct 5 13:27 pbi -rw------- 1 root www 94480204 Oct 5 13:26 plugins_jail-8.2.0-amd64.pbi
# ls -la /mnt/RaidVol total 25 drwxrwx--- 7 Fabian wheel 7 Oct 5 20:26 . drwxr-xr-x 4 root wheel 512 Oct 10 14:21 .. drwxr-xr-x 2 www www 2 Oct 5 13:27 .freenas drwxrwxr-x 6 Fabian wheel 6 Oct 6 17:06 data drwxrwxrwx 3 root wheel 3 Oct 5 13:26 jail drwxrwx--- 2 Fabian wheel 9 Oct 8 11:02 scripts drwxrwxrwx 4 root wheel 5 Oct 10 14:33 software