HELP!!! Can't access into Admin

Hi,

Today I wanted to access into Admin, but eveytime I try it I get this error:

Error: MySQL server has gone away
Error No: 2006
UPDATE oc_currency SET value = '1.00000', date_modified = NOW() WHERE code = 'EUR'

Opencart Version is 1.4.9.4

Please help me!

Thanks

I have read somewhere I must update table settings the field config_currency_auto to 0. But I can't find this table.