If you are getting this page disabled every time you start terminals as opposed to once time per day, then I would suspect a permissions issue with the LastUpdateCheck.txt. Can you see what is inside this file?
Terminals is supposed to create/update this file with contains the date and time when this check was performed. If this date is greater than or equal to your system date, it ignores the check.
Hence setting the contents of this file into the future should always ignore the check. (I tested this against the third build (21st Feb) and setting the date in the future does work)
For what it is worth, the check is comparing the build date against the rss feed at http://terminals.codeplex.com/project/feeds/rss?ProjectRSSFeed=codeplex%3A%2F%2Frelease%2FTerminals&ProjectName=terminals.
I think this feed was updated on the same day as the third build was built (21st Feb 2011) but unfortunately a few minutes later which is why terminals thinks it isn't the latest version.