In my case, I was looping through a series of objects from an XML file, but some of the instances apparently were not objects which was causing the error. Checking if the object was empty before processing it fixed the problem.
In other words, without checking if the object was empty, the script would error out on any empty object with the error as given below.
Trying to get property of non-object
For Example:
if (!empty($this->xml_data->thing1->thing2))
{
foreach ($this->xml_data->thing1->thing2 as $thing)
{
}
}