Database errors on multisite

I have a client running this plugin on a multisite install. It is version 3.7.1, and running version 1.0.2 of your plugin. (I know that neither of those are the latest version, but I’ve looked at the code and I think the issues reported below are still relevant for the latest versions.) We are having errors like this in the error log:

[31-Dec-2013 20:41:32 UTC] WordPress database error Table 'db.prefix_power_stats_pageviews' doesn't exist for query UPDATE prefix_power_stats_pageviews SET <code>hits</code> = <code>hits</code> + 1 WHERE <code>date</code> = '2013-12-31' made by shutdown_action_hook, do_action('shutdown'), call_user_func_array, power_stats_init, PowerStats->__construct, PowerStats->log_pageviews

In short, the database table it is trying to write to does not exist. I think that possibly this is due to a problem in the installation code. There is this line in wp_power_stats_activate():

if ($networkwide) {

However, $networkwide is not defined anywhere, so this will always be false.

In essence, the installation is not being performed correctly on multisite.

http://ww.wp.xz.cn/plugins/wp-power-stats/