It looks like the paths are just not working out correctly. The first thing you should do is check what value the Pear Path is set to just before the line that gives you an error. It seems that the path is not getting to this area the same as you are entering it.
To check on this put in this code just before the error line 15:
die("the pear path value is: " . $mailObj->PearPath);
This should stop execution and print out the message with the value for you. Let us know what it comes back with, also, post back with a copy of your page that has the UE on it and your UE folder from the site, I might help to have this code around as well.