On my test dev environment (Drupal + Civi 4.7.2), I added 3 contributions from the sample data to a new accounting batch. I then clicked the Close and Export button and chose CSV format. That resulted in this fatal error:
I then hit back on the browser and couldn't find Batch 1 as either closed or exported (in looking at the database (civicrm_batch), the status ID of Batch 1 was 5). I created a new batch (batch 2) and added different contributions and only closed the batch. I then went to Contributions > Accounting Batches > Closed batches and tried to export Batch 2 to CSV from that screen. I got the same Fatal Error as above.
Thinking that an upgrade might solve it, I upgraded my Civi install to 4.7.3 without incident.
I repeated my export to CSV batch tests (as noted above) and got the same Fatal Error.
I then tried both the Drupal and Wordpress 4.7 demos from demo.civicrm.org. I added three of the demo contributions to a new batch and tried to export to CSV. Both the Drupal and Wordpress demos white-screened.
I tried the same steps on the Drupal 4.6 demo at d46.demo.civicrm.org and it successfully exported the CSV.
Originally brought up here: http://civicrm.stackexchange.com/q/10202/105. Jon G encouraged me to file this issue.