Hello Ciarán
Guess you are using a quite old version of Membership Pro and it causes the issue. If I remember correctly, Joomla 3.4.4 changes the code of upload file API to prevent uploading zip file which contains PHP files inside (which is applied for this case). Plus, the latest EB PayPal Pro payment plugin might not compatible with old version of Membership Pro you are using
So for now, there are two choices:
1. Update to latest version of Membership Pro. You can drop me an email to tuanpn@joomdonation.com and I will send latest version to you for upgrading
2. If you want to use that old version (because you customized code for example), we will need to modify the code to allow the payment plugin to be installed. In this case, I need you to give me access to your site or FTP account. I understand your site might contains sensitive data which you don't want to give me access, if so, you can send metwo files
administrator/components/com_osmembership/controller/plugin.php
administrator/components/com_osmembership/model/plugin.php
I will modify these files and send it back to you so that you can upload it to your site to be able to install payment plugin
Regards,
Tuan
