The issue was due to anonymous function in a hook, now we fixed that by reverting to normal function, we believe now the plugin works fine with your configuration.
Sorry for the trouble, we have now rectified the issues. Tested with our servers and updated in wordpress plugin repository. Please try our new version and let me know if we can help anything else
We’ve checked the error you have reported. We didn’t replicate the same issue with nextgen and the line no 851 doesn’t exist in our plugin. We feel this error might be caused by other scripts.