Broken Wordpress plugin - clock shift issue?

For about six months, I was using the Wordpress plugin Twitter Tools to autopost a digest of the previous week’s tweets on my Dreamhosted blog.

All was well until a mid-2011 update to Wordpress, after which Twitter Tools’ digests stopped appearing. This has happened to other people who used the service. A few weeks ago, one of them suggested that the culprit seems to be a server whose clock has drifted off the right time.

I used the “date” command in PuTTY to check the time on my server, which seemed to agree with my laptop, which is synched with Are there any other date/time settings I should be checking?