when you say "intra site module" I assume that you are using an asp.net user control (ascx) file for the admin interface, is that correct? it sounds like there may be an issue with your markup, such as an unclosed div
the way I usually check for this is to go into the visual studio options, then under the html editor settings, tell it to "Format on paste". then I cut and paste the entire front end of the control markup back into place. if everything is correct it should format itself correctly, otherwise there is a problem with your html
an html validator like http://validator.w3.org
can help with this as well...
i hope this is helpful!