Launching Terminal Freezes the System for 5 Minutes in Mavericks
After Googling and trying a few things, I have got this resolved. As described here http://hints.macworld.com/article.php?story=20100623054627388 and elsewhere, there are a lot of log files accumulated in the the /private/var/log/asl directory. I downloaded Onyx http://www.macupdate.com/app/mac/11582/onyx and used it to delete the system logs and cache files. After restarting the computer, Terminal launches quickly. There are no delays when logging in from SSH or from the log-in screen either.

The error message from ssh-add seems to be a different problem.