Posting has been slow lately on the stblogs.org sites because of a malfunction on the system hosting them. By upgrading another software package on the machine, the people at our hosting provider made MT break. Here's info on the problem in case any other MT webmasters have been seeing the same problems.
To workaround the problem, I installed a private copy of Perl modules DBI and DBD::mysql, to take them both back to a slightly earlier version. That seems to have corrected the trouble.
Update: (7/9) The author of DBD put out an updated version, which helped somewhat, but the problem remains when authors post or re-save long entries. I'm continuing to check for progress from the developers.
Howdy, RC.
I started posting not long before 11pm CDT and noticed this problem after 11pm (midnight your time, I suppose?)
The italics in my last post are my fault. I then edited the post after seeing my mistake and began receiving the error you mentioned.