Debug: PHP Notice Undefined variable

I have this PHP Notice when active wp_debug.

Notice: Undefined variable: onclick_attr in wp-content/plugins/posts-by-tag/posts-by-tag.php on line 942

Notice: Use of undefined constant disable_cache - assumed 'disable_cache' in wp-content/plugins/posts-by-tag/posts-by-tag.php on line 473

I’m not a programmer but i’ve solved the first error with this:

if ( $onclick != '' ) {
 $onclick_attr = ' onclick = "' . $onclick . '" ';
 }

on line 911 and second error with a $ before disable_cache on line 474:

if (!$disable_cache) { // store in cache

I hope you can fix it on next release!

https://www.ads-software.com/extend/plugins/posts-by-tag/