WordPress suddenly won’t edit/add posts in v.2.1.3

HELP! Please see my previous request for help in the troubleshooting forum; I’m having a problem with an error message that will not let me edit drafts or old posts, or even create new posts. It has been intermittent. (FYI, I’m running v. 2.1.3, although your selection box above won’t let me select anything higher than 2.1.1.)

https://www.ads-software.com/support/topic/117162?replies=1

Thanks – Carolyn Bahm
FYI, my blog is at https://www.loopyknits.com if it helps to look at it?