Image problem on single page

Hi,

Im having some trouble with images in my single post’s page.

Let me explain the major problem: in my main page, i can see the full post, with images, text, links and everything else. But, when i click to see the post on his single page, i have the following problem:

Only appears the image, like in the media page. The URL keeps the same of the post, but what i see is the single media in page (no text).

I noticed that, in the posts im having this problems, the main image is unattached from the gallery. And when i attach the image, the problem is solved.

I really want to know why is this happening, somebody can help me??

Thanks, and sorry about my poor english (im trying to improve it).