Reinstalled phplist, now FCKEditor doesn't work

Hi, I had to migrate a phplist installation and files were missing so I installed fresh, however now the FCK Editor is not working. It presents a blank screen when loaded directly and the iframe is empty on the ‘start a message’ screen.

Is there a way to debug this? I tried the fck debug php script but it displays blank.

I did switch from Apache to nginx and I am wondering if there might be something wrong with my configuration. Also I changed the location of the root folder for phplist, but I did update the configuration with the new paths.