DB cannot save forms from web - but only this one DB!

Has anyone gotten an http 404 error when attempting to save forms from the web? This now happens in my database no matter what I do, even though identical code in another database on the same server works fine. Any clues, or is my main db simply got a corrupted design?

I have a normal MainForm with a button @Command([Compose]; “Response”); which seems to work fine to create the response (including inheriting data). But no matter how I try to save the response, I get a 404 error and the data is not saved in the db.

I’ve tried creating a new kind of NewResponse form (incase the UNID of the Response form design element is hosed); I’ve tried using both Buttons on the page with a variety of [FileSave], [CloseWindow], blah blah blah on them; I’ve tried using an Action Bar with [FileSave]s in it both as HTML and Applet, and all give the same 404 error. Another DB on the same server, this code works just fine.

The only major change recently was upgrading the server hardware from XP to Linux, but I’ve double-checked the CaSIng of the .nsf name and it’s fine.

Watching the http error logs shows a number of GETs going through fine to various MainForm elements. Then a nice POST comes along with what seems like a proper format, including the right Response UNID and ParentUNID set. And then I get a 404 back. Arggg!

My best guess is that the (ancient) design of this DB is so large that something in the guts of the design has gotten hopelessly corrupted. Other ideas appreciated, including using some other method to save my responses.

Oh, server is 653 on latest RHEL.