Fatal error: Uncaught exception ‘SmartyException’ with message ‘unable to write file

El otro dia me encontre con este error:

Fatal error: Uncaught exception ‘SmartyException’ with message ‘unable to write file /var/www/vhosts/MiDominio/httpdocs/cache/smarty/compile/5a/5c/7b/wrt53c28bab1fdaa6.01547362’ in /var/www/vhosts/MiDominio/httpdocs/tools/smarty/sysplugins/smarty_internal_write_file.php:44 Stack trace: #0 /var/www/vhosts/MiDominio/httpdocs/tools/smarty/sysplugins/smarty_internal_template.php(201): Smarty_Internal_Write_File::writeFile(‘/var/www/vhosts…’, ‘compileTemplateSource() #2 /var/www/vhosts/MiDominio/httpdocs/classes/module/Module.php(1860): Smarty_Internal_TemplateBase->fetch() #3 /var/www/vhosts/MiDominio/httpdocs/modules/leomanagewidgets/leomanagewidgets.php(479): ModuleCore->display(‘/var/www/vhosts…’, ‘/themes/leomana…’, ‘leomanagewidget…’) #4 /var/www/vhosts/MiDominio/httpdocs/modules/leomanagewidgets/leomana in /var/www/vhosts/MiDominio/httpdocs/tools/smarty/sysplugins/smarty_internal_write_file.php on line 44

Fatal error: Call to undefined function mcrypt_encrypt() in /var/www/vhosts/MiDominio/httpdocs/classes/Rijndael.php on line 50

Para solucionarlo le doy los permisos necesarios a la carpeta cache, y me encuentro con lo siguiente
Table ‘XXXX_bd.ps_leobtslider’ doesn’t exist



Borro la carpeta leobtslider del directorio modules, ya que no lo uso

Y me encuentro con este otro:
Fatal error: Call to undefined function mcrypt_decrypt() in /var/www/vhosts/MiDominio/httpdocs/classes/Rijndael.php on line 70

Cambio el valor del registro PS_CIPHER_:ALGORITHM en la tabla ps_configuration de 1 a 0

Y Solucionado!!
Espero os sirva de ayuda

Fuente:
http://spitzersoftwaresolutions.blogspot.com.es/2012/05/prestashop-blank-bo-and-fo-because-of.html