Sorry , I was out line for some days cause work, yes, I use the version 0.9.4.6 on a hosting Windows, and I had the same problem, I understand that the solution I have used is just a trick to fix the problem without analyze why the issue is present ( I am novice to php and i have not analyzed the plugin code ), I just thought that was like windows had problems to use the null value so I tried that trick . Thanks You
If can help, I solved the same error changing the default value of the field ‘registered’ in the table wp_sendpress_subscribers from null to 0, my site is on windows
