Product Export - Dataflow Profiles takes to 500 error page

Question

I'm trying to export products from Magento 1.8.1.0 but when I go to the following location, it just comes with a 500 page error straight away.

System > Import / Export > Dataflow - Profiles

I checked the logs and it has been narrowed down to this:

PHP Fatal error: Class 'Unserialize_Reader_ArrKey' not found in magento/lib/Unserialize/Reader/Arr.php on line 88

How can I fix this? It looks like a patch might not of been applied properly or something.

Thanks

Answer 1

If you are on Magento 1.8 something went wrong ...

Unserialize_Reader_Arr, Unserialize_Reader_ArrKey, Unserialize_XYZ were added in Magento 1.9.2.2.

Edit:

These files were also part of SUPEE-6788. Please check if the patch was applied correctly.

Download: https://magento.com/tech-resources/download