Error when enabling module using Drush

When enabling the latest 7.x-2.x-dev module using Drush, I get the following errors:

$ drush en addthis
The following extensions will be enabled: addthis
Do you really want to continue? (y/n): y
Invalid argument supplied for foreach() block.module:389
Invalid argument supplied for foreach() block.module:389
Invalid argument supplied for foreach() block.module:389
Invalid argument supplied for foreach() block.module:389
addthis was enabled successfully.