On a 64 bit dedicated server we came accross an error:

[root@server ~]# php -v
Failed loading /usr/local/ioncube/ioncube_loader_lin_5.2.so:
/usr/local/ioncube/ioncube_loader_lin_5.2.so: wrong ELF class: ELFCLASS32

If you come across such issue it seems that you have installed the wrong version of the IonCube Loader. For 64 bit remember to use the path /usr/lib64/php/modules/ioncube

I hope this helps you!