I've been doing a deep dive into your plugin code and I noticed that you use two pieces of code that send an item to Apache's error log. These are:
1) error_log('login/register redirect - '.$redirect); (in loginregister.php)
2) error_log('logged into linkedIn, no signoff though.'); (in linkedinprofile.php)
Are you using these merely as flags so you can trace what is happening, or are these real errors?
I don't think either of those are part of our original code. The 'error_log' function call is a native PHP call. When we do logging in our extensions, we use JLog, which is the Joomla logger utility class.
Are you sure you didn't add that code? I just searched our code and couldn't find any reference to the above calls you mentioned.