Image upload troubleshooting

I've been using webassist extensions for many years and am very familiar with the file manipulation upload wizard. I need help trouble shooting an image upload problem that has me totally stumped. When modifying an existing record, I can't get the page to upload a new image. The insert page uploads just fine.

I've made sure the enctype="multipart/formdata" is in the form tag.
I've compared the insert to the upload page.
It doesn't appear to be a file size issue (Even extremely small jpgs fail to upload.
It's not a permissions problem with the target folder (as it works just fine on the insert page).
I've inserted the error reporting code as indicated on other threads.

I've attached the problem page (incidently, the other two table data assist forms fail to work on the upload pages as well), as well as the working insert page. I'll post FTP information in a private message in case you want to look at it directly on the server.