Fatal errors after migration to hosting

I made a website for a client in local host using a artisteer 4.1 generated theme and polylang 1.5 plugin. In localhost everything worked fine but once I migrated it to GoDaddy hosting there was problems. I couldnt also use the duplicator plugin to migrate it because there was some problems with GoDaddy. The site is jurisprudentia.fi

The problems is strange since it only gives the following error sometimes. First it was showing more often but then I ran the search and replace plugin and changed the permalinks back and fowards so it started to show only now and then:

Fatal error: PLL_Model::_languages_list(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition “PLL_Language” of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /home/content/p3nexnas05_data01/52/2115852/html/wp-content/plugins/polylang/include/model.php on line 192

Can some help me with this problem? Can you say what causes this problem by the error code it gives? Im not really good in php.

Thank you a lot allready in advance.

Mikko