I'm happy to say I've found the right knob to twiddle in the engine room to get the site running right.
To recap - on Monday last week the host running this site had a hard crash and for most of last week V was down while files were being restored off of backup. The site was working after a fashion, but it appeared unable to create new posts etc..
I've got that worked out now (as you can see), and some other aspects of the site are working well again.
Unfortunately the recently uploaded files are still missing. The dreamhost staff is still working (supposedly) on recovering those files.
In the meantime I'm researching one or another service to use instead of dreamhost.