Why wont this Plist run at login?

Question

typing this in manually in terminal works fine:
/opt/local/bin/daemondo --label=thin --start-cmd /usr/local/bin/thin start -s 3 -C /etc/thin/thin.yml --pid=none
I've tried loading the plist in both /Library/LaunchDaemons/ and ~/Library/LaunchAgents. (sudo launchctl load -w /paths/mentioned -- however I get launchctl: Dubious ownership on file (skipping) -- so I use sudo launchctl load -F for ~/Library/LaunchAgents/thin.plist).
Neither seem to work.
Here's the plist on pastebin.
http://pastebin.ca/922156
Please tell me what is wrong with it -- I'm losing my sanity.

Answer 1

if including these program arguments are giving you a headache, how about making a simple executable script (permissions 755) that reads
#!/bin/sh
/opt/local/bin/daemondo --label=thin --start-cmd /usr/local/bin/thin start -s 3 -C /etc/thin/thin.yml --pid=none
exit 0
then making your plist refer to the full path name to the above script, with no program arguments necessary?
See if manually launching the new script does what you want, then doublecheck that the script's permissions are 755 and that ownership and group affiliation are correct. The plist, as gnarlodius has said, should be 644.
Question: do you want this to run at system boot-up or reboot, or at user login? That determines in which LaunchDaemons or LaunchAgents directory that the plist belongs, as well as influence your choice of path to the script. Will also affect your choice of ownership and group affiliation or what user/group the plist should execute the script as.