Hi Victor,
We actually sent them the code to fix that issue about 6 months ago. ??
The Event Espresso developers had contacted us and we responded back within an hour of them writing us, and provided them with the code they need to fix the compatibility using WP-SpamShield’s hooks (code that other plugins can “hook” into). For best security it should be fixed on their end. It’s only about 4 lines of code and quite easy to implement. Unfortunately I guess it hasn’t been implemented.
If you’ve already gone into your settings, and used the option “Disable anti-spam for miscellaneous forms.”, then the plugin wouldn’t be blocking PayPal IPN any more.
When you make a change to your site, and nothing happens, there may be a caching issue. Does your website have server caching or any caching plugins installed? If so, you should clear the cache after each time something is change on your site.
If you haven’t had a chance to yet, please take a few minutes to work through the FAQs and Troubleshooting Guide.
If working through the FAQs and Troubleshooting Guide does not fix things for you, then I’ll need you to head over to the WP-SpamShield Support page (our main support venue), and submit a support request. We’ll need to get a little bit of additional info, and email back and forth with you.
– Scott