第51行的PPModel.php中的PayPal REST API问题

Whenever I try to create payment on paypal using create.php, it gives me this error

Fatal error: Class 'string' not found in public_html/demos/demo_files/integrate-paypal-rest-api-php-mysql/vendor/paypal/sdk-core-php/lib/PayPal/Common/PPModel.php on line 51

I am not able to find any help regarding it anywhere. PPModel.php is part of PHP SDK by PayPal. PPModel.php can be found here The script works fine on localhost, but on webhosting server it gives following Fatal error.

Update I was able to fix the issue by disabling eaccelerator for php. Caching plugins such as eaccelerator, opcache, APC might create problem for others also