How to prevent my plugin break design of the site?

[postcd]

Hello, i have created new plugin where its "Hook Location" is navbits_complete

The PHP code is:
readfile('http://feeds.1ous.com/?123456');

My aim is to include that remote file on all pages of the forum including index

I prefer footer location. But this way when i Quick edit some post, its design is damaged:
Attachment 156926

I am using default vbulletin 4 style.

When i remove the "readfile" line, problem persist, but when i disable plugin, it is fixed.
Please which Hook location to use and which PHP code to use in plugin so the included file does not break the design of the quick reply?

[Seven Skins]

PHP file may be spitting out some text or something hence this issue.

[postcd]

My aim is to include remote file into vbulletin code (i tried via plugin/hook) so it appears on all pages including index.
Or how to adjust code (i can NOT adjust remote "file" http://feeds.1ous.com/?123456 code) so it do not damage vbulletin design / Quick editor?