Categories/products blank in admin area

I just upgraded from v1.3.8a to v1.3.9d. When I go to the admin area and click on the categories/products link it goes to a completely blank page. The other links I've tried have worked fine. The link seems to be pointing to exactly where the file (categories.php) is located. I get just a white page without ANYTHING on it at all.

Did you check to see that admin/categories.php exists and wasn't corrupted during the upgrade ?

The file is there. I don't know how to determine if it was corrupted. Would it be obvious?

Easiest just to overwrite it with a fresh copy from the Zencart zip file.

Ah! I found the problem. It wasn't the categories.php file itself but a file it used. It was missing. In fact, a whole folder was missing! Because I have a very slow dial-up connection I had to upload files a few at a time over several days. That's how I missed this folder. I tried to double check everything but somehow still missed this one.

I think it's fixed now. Thank you for your suggestions!

In the future, when doing a new installation, try uploading the Zencart zip file and extracting the files using your hosting control panel's File Manager. if possible. Much faster, and prevents problems like this.