Okay 5.4.0d2 is definitely ONLY available from HEAD, so whatever or whoever did something on your site must have gotten the HEAD version. And it might be that you installed something from the repository? Maybe something is wrong there ?
Last but not least, the error you are describing should not happen anymore with the latest version of site-node lazy caching (albeit I need to fix the DB hits, see the forum posting, anyone any idea?). So, if you really depend on acs-tcl 5.4 for whatever the reason (maybe because you installed acs-mail-lite from head, or project-manager or contacts), then make a fresh checkout. Be warned though that we do have a performance issue and you might just install acs-tcl 5.3.1.
