Plugin Database errors

Our web hosting (Blue Host) has tracked and checked our website often happen “an error occurred while processing this directive” error cause of your plugin have database error.

Please see the following error log and could you help to resolve this urgent issue? Thank you.

***error_log excerpt***

[18-Apr-2014 21:21:24 UTC] PHP Fatal error: Call to a member function has_cap() on a non-object in /home/vsviporg/public_html/vantageshanghai/wp-content/plugins/alipay/includes/fnc.core.php on line 848
[18-Apr-2014 21:21:26 UTC] PHP Fatal error: Call to a member function has_cap() on a non-object in /home/vsviporg/public_html/vantageshanghai/wp-content/plugins/alipay/includes/fnc.core.php on line 848
[18-Apr-2014 21:39:27 UTC] WordPress database error Illegal mix of collations for operation ‘ IN ‘ for query
SELECT
target.post_id, sum(target.weight * log(968 / least(968, freqs.freq))) as score
FROM
wp_wp_rp_tags as target,
(SELECT label, count(1) as freq FROM wp_wp_rp_tags
WHERE label IN (‘P_moma’, ‘P_new york’, ‘P_sound art’, ‘C_艺述’, ‘A_art’, ‘A_alt’, ‘A_div’, ‘A_ap’, ‘A_a’)
GROUP BY label
) as freqs
WHERE
target.post_id NOT IN (‘15834’) AND

target.label=freqs.label AND
target.label IN (‘P_moma’, ‘P_new york’, ‘P_sound art’, ‘C_艺述’, ‘A_art’, ‘A_alt’, ‘A_div’, ‘A_ap’, ‘A_a’)
GROUP BY target.post_id
ORDER BY score desc, target.post_id desc
LIMIT 10; made by require, require_once, include, the_content, apply_filters, call_user_func_array, wp_rp_add_related_posts_hook, wp_rp_get_related_posts, wp_rp_fetch_posts_and_title, wp_rp_append_posts, call_user_func, wp_rp_fetch_related_posts_v2

https://wordpress.org/plugins/alipay/