error 141 of install type

[kobe]

if one hard disk has 2 systems,and one of them is Ubuntu,then it causes "error 141" in Ubuntu 12.04 LTS. In ubiquity,the fuction calculate_autopartitioning_options() has an error when it goes to "elif os_count == 2 and len(ubuntu_systems) == 1:". if it goes to "if 'replace' in self.extra_options:", the variable "ubuntu" defined ,but if it can not go to this if ,when it is "q = 'ubiquity/partitioner/ubuntu_and_os_format' ", it quotes the undefined variable ubuntu in " self.db.subst(q, 'CURDISTRO', ubuntu)". So ,the "error 141"
happend.