Thank you for the login credentials, and your detailed description.
Here are the answers:
1) I login to your site and created and saved a manual journal document without problem (doc number is MJ00002). How the problem can be reproduced, e.g. what data have you entered when you got the error 500? (Or maybe the problem occurs with the old release?)
2) I have activated the plugin on your site. I had to deactivate and activate a plugin again (not the license but the plugin). After it the license could be activated without any problem. This is a problem that occurs in some installations, we will fix it soon, but it is right on your site now.
3) Invoice designer (the exact name is Doc Customizer) is working on your site.
Earlier you wrote me, that “Doc designer also showing 500 internal error”. Since then the new release was issued. Now I cannot find any problem (I made a “TEST SKIN” on your site, set a purple border for the items and save the document skin without any problem). If the problem still occurs, please give me more information how can it be reproduced.
4) I wrote you a privet mail about the Reports problem on your site. I need your permission (just an e-mail) to deactivate your other plugins on your site to see which one conflicts with Filogy Reports.