When I try to install the Gallery module I get this error (After I create a gallery page, upload some images into the correct gallery folder, then try to view the page in the main site):

XML Parsing Error: junk after document element
Location: http://localhost/silverstripe/gallery/
Line Number 2, Column 1:<b>Notice</b>: Undefined index: start in <b>C:\wamp\www\silverstripe\gallery\code\GalleryPage.php</b>; on line <b>381</b><br />

I just downloaded the Gallery module, put the "Gallery" folder in my root silverstripe directory, then ran /db/build. Then I went into the CMS and created a Gallery Page, and uploaded some images. Im running the latest version of Silverstripe and only just downloaded the Gallery module, so it should be the latest version too.

Any ideas?

Try removing the <?xml> tag from the html document?