Oracle password has expired, however I have no way of changing it

When I connect to my local development database, I get an error saying the password has expired. I've been trying to change it with sqlplus to no avail:

C:\>sqlplus TPMDBO/password@localhost/global

SQL*Plus: Release 11.2.0.3.0 Production on Wed Nov 6 15:41:02 2013

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

ERROR:
ORA-28001: the password has expired

Changing password for TPMDBO
New password:
Retype new password:
ERROR:
ORA-01017: invalid username/password; logon denied

Password unchanged

I get this error no matter what new password I type in.

My main question is how I can reset this password. However, I'm also curious if there's a way to make the password never expire. This is a local dev database, I really don't care about the security or anything and none of the data on it is important.

If the account is locked, as far as I know, the user can't change it. The Oracle output in your question shows the account is not locked, but expired.

Log in to your database as a user who has privilege to alter other users (for example, SYS) and issue the following command:

ALTER USER tmpdbo IDENTIFIED BY new_password;

You can change the expiration behaviour. There already was a question about that on Stack Overflow:

Make Oracle Password Never Expire

StackExchange Database Administrators Q#52929, answer score: 13