You're using a version of the plugin that was made for b2evolution 2.3 or greater. If that's the only problem you're having, then you can comment out the part of the plugin that clears the cache. But, of course, upgrading your blog is the best thing to do.

What a coincidence! I was just playing with ministats and got two different errors depending on how I tried to call it. Plugin->call_by_code didn't like like ItemList in line 237, and more to the point calling it as a widget in the sidebar gave me something like "Table 'xxxxxx_b2evolution.T_items__prerendering' doesn't exist(Errno=1146)", although it was NOT the prerendering table. I believe it was T_items__item, but I simply pulled the widget and the plugin. I was playing with it on my live installation and have no time to work on it is why.

Ahhh... I didn't realize anything special had to be done since the [url=http://plugins.b2evolution.net/index.php/2007/02/12/astonishme_digg_plugin]page for this plugin[/url] lists "1.8+, 1.9, 1.10, 2.x". Perhaps that needs to be edited to reflect the new code, or your instructions below could be added to the included .html file.