After setting these errors:
Warning: file_get_contents() [function.file-get-contents]: URL file-access is disabled in the server configuration in /path-to-wordpress/wp-content/plugins/wp-statusnet/wp-status-net.php on line 548
Warning: file_get_contents(
http://tinyurl.com/api-create.php?url=h ... 3/31/test/) [function.file-get-contents]: failed to open stream: no suitable wrapper could be found in /path-to-wordpress/wp-content/plugins/wp-statusnet/wp-status-net.php on line 548
Warning: Cannot modify header information - headers already sent by (output started at /path-to-wordpress/wp-content/plugins/wp-statusnet/wp-status-net.php:548) in /path-to-wordpress/wp-includes/pluggable.php on line 897
Maybe it doesn't work in multisite-environment ?