WebDav stalls at end of large upload

Greetings. I’m wondering if anyone can shed a little illumination on a very annoying problem.

I’ve set up a WebDAV share on my DH account. It works just fine, except that when I copy a file from my local drive to a folder in the WebDAV share, the copy zips along at a good 10 MB/s or so and then pauses as if hung right at the end of the upload. For small files the pause is short; for files of 50 MB it can be many seconds; and for files of a few hundred MB it can be many minutes. If I wait long enough the upload finishes successfully, unless a network interruption causes the share to disconnect abruptly. And that kind of interruption seems to happen often enough that I haven’t yet succeeded in uploading a 500 MB file, despite many attempts.

I have no such problem with WebDAV uploads to a share on a server in my building, so I suspect it’s something about the DreamHost setup.

(I’m using OS X 10.4.8.)

Any thoughts?