I am getting this error when trying to download my products. I am helping a friend. Not familiar with her store, but trying to help. Magento ver. 22.214.171.124
Fatal error: Unsupported operand types in /home/beemer/public_html/cart/includes/src/Mage_ImportExport_Model_Export_Entity_Product.php on line 875
You are using compilation feature of the Magento.
Go to Magento Admin Panel -> System -> Tools -> Compilation -> Disable and disable the compilation.
After this clear caches from var/cache folder and try to export again.
It should work for you.