Hello.
I am new to this forum and new to OW.

Trying to install v1.2.4 on my localhost(wampserver 2.1), I had the error cannot connect to the database.

I did some snooping in the ow_core/database.php and found this on line 213.

if ( !isset($params['host']) || !isset($params['username']) || !isset($params['password']) || !isset($params['dbname']) )
{ 

I have no password so I changed it to

<pre>
            if ( !isset($params['host']) || !isset($params['username']) || !isset($params['password']) || !isset($params['dbname']) )
            {
</pre>

if ( !isset($params['host']) || !isset($params['username']) || !isset($params['dbname']) )
{

and it worked perfectly.
However, the generated config for me had 

define('OW_DB_PASSWORD', '{$db_password}');

and therefore failed to connect on the plugins page.

I have fixed it, but thought I should post this to help the devs track this down.

Hope I helped.