error with upload after upgrade to v2.03

I made a minor version upgrade to 2.03 and am seeing an odd error when attempting to save an upload. Here's what happens:

Browse, select file, click "upload". Upload completes. A preview image and deteails are visible. Okay so far... but, then...

Click "Save" (for the first time) and a "Message from Web Page" popup appears with a yellow caution arrow graphic, and a random number, like "6" or "32".

I close the popup.

If I click "Save" (for the second tiime), error popup says "File uploads is required! You must upload a file!

If I click "remove" error popup says "Error: Upload not found!".

If I click "modify", error popup says "No matching records were found".

If I click "cancel", returning to the list view, I see the item and can then click "erase".

I verified through FTP that the files are being uploaded to the server and thumbnails are also created.

Permissions all seem to be fine. What should I check?