This issue could be due to different reasons.
1 - Firstly start by cleaning your cache and check.
2 - Then make sure you have not disabled Mage_log as described here
To do that you execute this in your magento docroot:
grep -A 5 -r '<Mage_Log>' app/etc/modules
You should see something like this:
<Mage_Log>
<active>true</active>
<codePool>core</codePool>
Next check in the admin panel in
System->Configuration->Advanced->Advanced
see if the module output is enabled there as well.
3 - Finally this issue happens when there is no resource defined for a given Model. To find out which is the Model that is failing you can add a log to this file:
app/Mage.php in line 254.
It should look like this:
public static function registry($key)
{
if (isset(self::$_registry[$key])) {
return self::$_registry[$key];
}
Mage::log(self::$_registry[$key], 1, 'issue.log');
return null;
}
Then you can check your log file in here: var/log/issue.log
Or if you want to do it quick and dirty do it like this:
public static function registry($key)
{
if (isset(self::$_registry[$key])) {
return self::$_registry[$key];
}
die(self::$_registry[$key]);
return null;
}
Make sure to revert the code changes once you find the issue.
