There was a small error in the newest release of the contribution
plugin:
http://omeka.org/forums/topic/getting-the-contribution-plugin-to-work
As noted by dawit, on line 26 of the add.php file in the plugin’s
theme folder, the uri listed the path to the partial as ‘contribution/
contribution/’ – shave one of those off and it works correctly. Line
26 should read:
var uri = "<?php echo uri('contribution/'); ?>" + partial;
These changes are now reflected in the newest downloadable version of
the contribution plugin.
Dave Lester