Suffering almost the exact same problem as the user on this thread:
Except I'm using the prepared AWS ubuntu LAMP stack instance from Bitnami. I have uncommented ;extension=imagick.so in /opt/bitnami/php/etc/php.ini and restarted but keep getting this error in the apache error log:
no decode delegate for this image format `PDF'
I've checked that all the imagick extension is where it should be but even the most simple imagemagick php test code won't run properly.
The user on the other thread worked with someone to try and solve the issue and then the thread was locked without resolution.
Again any help much appreciated.