Can't update database from 1.7.1 -> 1.7.6 via one click upgrade

[Henrik]

I am getting this error.

OK] SQL 1.7.7.6 ALTER TABLE `ps_currency` MODIFY COLUMN `numeric_iso_code` varchar(3) DEFAULT NULL NULL<\/div>","Database upgrade OK"],"nextErrors":["[INTERNAL] \/home\/xxxx\/public_html\/classes\/Validate.php line 36 - Cannot declare class ValidateCore, because the name is already in use","[INTERNAL] \/home\/xxxx\/public_html\/classes\/Validate.php line 36 - Symfony\\Component\\Debug\\Exception\\FatalErrorException: Compile Error: Cannot declare class ValidateCore, because the name is already in use\n#0 {main}"],"error":true,"next":"error"}"

How do people upgrade the database from 1.7.1 -> 1.7.6 without going crazy?