[Plugin: Netxgen gallery] Can not upload files

Hi to all,

I got an error everytime i try to upload a new file.

My domain is: http://www.corsifotografia.pro

The message i receive from the plugin is:
An unexpected error occured. This is most likely due to a server misconfiguration. Check your PHP error log or ask your hosting provider for assistance.

My hosting provider said that the error is:
Failed loading /opt/php54/lib/php/extensions/no-debug-non-zts-20100525/ZendGuardLoader.so: /opt/php54/lib/php/extensions/no-debug-non-zts-20100525/ZendGuardLoader.so: undefined symbol: zend_new_interned_string, referer: http://www.corsifotografia.pro/wp-admin/admin.php?page=ngg_addgallery

Any idea to solve that problem?
Thanks DamonCarter