[Plugin: Testimonials Widget] PHP warning

First of all let me say, this is a brilliant plugin, I have no problems with it on normal posts / pages. However I have a custom post type which makes a call to a non-WP database and I am getting the following errors from the testimonial widget, which appears after this content:

Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: Access denied for user ‘gianlucar’@’localhost’ (using password: NO) in […]/wp-content/plugins/testimonials-widget/testimonials-widget.php on line 67

Warning: mysql_real_escape_string() [function.mysql-real-escape-string]: A link to the server could not be established in […]/wp-content/plugins/testimonials-widget/testimonials-widget.php on line 67

According to various online sources it has something to do with a database call not being made (correctly), but I don’t understand enough about PHP to debug. And I have no idea who gianlucar’@’localhost is either! Do you have any advice as to what could be causing this or what I would need to do to fix it?

Many thanks in advance for any pointers you can provide.

http://wordpress.org/extend/plugins/testimonials-widget/