WordPress MU

My posts display my images correctly. My main page/sections display an error instead of a thumbnail. The error shows 'phpThumb', the path and 'does not exist'. The path includes /files/ which is the DB location. I duplicated the path on my site and the thumbnails do show up. I am using Plesk 8.1. Other than this I am not having any problems with the database. What do I need to do to correct this?

Are you using a theme that is supposed to pull in a thumbnail for a featured post?

Thanks Andrea. I've tested 2 different themes and it does the same thing on both of them.

But are they both themes that pull in a thumbnail for a featured post?

The code a lot of theme authors use for that breaks in MU. If that's your issue, I can give a link to a plugin to fix it.

If not, I need a link so I can see it.

I assumed that they pulled in thumbnails since the themes have phpthumb files in the scripts folder. The themes I have been using are Comfy 2.1 and 2.5. If this theme is breaking the thumbnails I would greatly appreciate the plugin. Thank you.

Many magazine themes with auto thumbnails do break in MU. this should help:
http://justintadlock.com/archives/2008/05/27/get-the-image-wordpress-plugin

Thanks. I have installed get-the-image and it doesn't fix the problem. I'm using WPMU if that makes a difference.

I didn't have this problem with WP.