Reboot from the command line (stuck processes)
If you can't kill something with -9, and sudo reboot doesn't work, you're pretty much out of options. The process is deadlocked in a manner that has prevented the OS from shutting down.

Have you closed all other Windowed applications? talagent is apparently the process that manages Resume, your guess is as good as mine in determining why it's deadlocked; Errors communicating with a process it was trying to save before closing, disk errors, etc. Since it's attempting to exit, it's unlikely that anything else (forcing system sleep, closing the process it was waiting on) will cause this process to work out it's lock.

The power button is necessary at this point.