I recently wanted to upload an Open Office presentation to WordPress 2.1 and received the message:

File type does not meet security guidelines. Try another.

It turns out that WordPress limits the types of files you can upload. Fixing it was pretty simple. You just need to look for the function wp_check_filetype() in the wp-includes/functions.php file and add the following.

'odt' => 'application/vnd.oasis.opendocument.text',
'ott' => 'application/vnd.oasis.opendocument.text-template',
'oth' => 'application/vnd.oasis.opendocument.text-web',
'odm' => 'application/vnd.oasis.opendocument.text-master',
'odg' => 'application/vnd.oasis.opendocument.graphics',
'otg' => 'application/vnd.oasis.opendocument.graphics-template',
'odp' => 'application/vnd.oasis.opendocument.presentation',
'otp' => 'application/vnd.oasis.opendocument.presentation-template',
'ods' => 'application/vnd.oasis.opendocument.spreadsheet',
'ots' => 'application/vnd.oasis.opendocument.spreadsheet-template',
'odc' => 'application/vnd.oasis.opendocument.chart',
'odf' => 'application/vnd.oasis.opendocument.formula',
'odb' => 'application/vnd.oasis.opendocument.database',
'odi' => 'application/vnd.oasis.opendocument.image'