manofstone

Okay, I ran into the same issue. Here is how I fixed it.

In wp-content/themes/gallery

edit the style.css file

around line 380 comment out using /* */ or delete the following entry

.page #content{
   margin-left: 320px;
   width: 620px
 }

hope this helps someone else with the same problem. This is where all the formatting should be modified if you are editing the gallery child theme of thematic.