Magento cron tab problem

Question

I have the following in config.xml in order to set up a cronjob with magento

<crontab>
    <jobs>
        <mycompany_mymodule>
            <schedule>
                <cron_expr>* * * * *</cron_expr>
            </schedule>
            <run>
                <model>mymodule/observer::editEntries</model>
            </run>
        </mycompany_mymodule>
    </jobs>
</crontab>

my controller is:

class Mycompany_Mymodule_Model_Observer{
    public function editEntries() {
        /****************/
    }
}

and i am getting the following error:

'exception ''Mage_Core_Exception'' with message ''Invalid callback: mymodule/observer::editEntries does not exist'' in C:\xampp\htdocs\magento\app\Mage.php:595
Stack trace:
#0 C:\xampp\htdocs\magento\app\code\core\Mage\Cron\Model\Observer.php(301): Mage::throwException(''Invalid callbac...'')
#1 C:\xampp\htdocs\magento\app\code\core\Mage\Cron\Model\Observer.php(72): Mage_Cron_Model_Observer->_processJob(Object(Mage_Cron_Model_Schedule), Object(Mage_Core_Model_Config_Element))
#2 C:\xampp\htdocs\magento\app\code\core\Mage\Core\Model\App.php(1338): Mage_Cron_Model_Observer->dispatch(Object(Varien_Event_Observer))
#3 C:\xampp\htdocs\magento\app\code\core\Mage\Core\Model\App.php(1317): Mage_Core_Model_App->_callObserverMethod(Object(Mage_Cron_Model_Observer), ''dispatch'', Object(Varien_Event_Observer))
#4 C:\xampp\htdocs\magento\app\Mage.php(448): Mage_Core_Model_App->dispatchEvent(''default'', Array)
#5 C:\xampp\htdocs\magento\cron.php(74): Mage::dispatchEvent(''default'')
#6 {main}'

full config.xml

<config>
    <modules>
        <mycompany_mymodule>
            <version>1.0.0</version>
        </mycompany_mymodule>
    </modules>

    <global>
        <models>
            <Mymodule>
                <class>Mycompany_Mymodule_Model_Observer</class>
            </Mymodule>
        </models>
    </global>

    <crontab>
        <jobs>
            <mycompany_mymodule>
                <schedule>
                    <cron_expr>* * * * *</cron_expr>
                </schedule>
                <run>
                    <model>mymodule/model_cron::editEntries</model>
                </run>
            </mycompany_mymodule>
        </jobs>
    </crontab>
</config>

----- ediit -----

so the cron attribute should look like this?

<crontab>
    <jobs>
        <mycompany_mymodule>
            <schedule>
                <cron_expr>* * * * *</cron_expr>
            </schedule>
            <run>
                <model>mycompany_mymodule_model/observer::editEntries</model>
            </run>
        </mycompany_mymodule>
    </jobs>
</crontab>

Answer 1

You have missing model and you need to define models Just add models to config.xml

<global>
    <models>
        <mymodule>
            <class>Mycompany_Mymodule_Model</class>
        </mymodule>
    </models>
</global>

And Observer.php localation is app/code/yourmodulecodepool/Mycompany/Mymodule/Model

Edit:

Issue1:

as you have set mymodule/observer .That mean mymodule/observer

mymodule is a model class prefix which in config.xml

your code is model prefix and always be in lower letter

<global>
        <models>
            <mymodule> <!--  change <Mymodule> to <mymodule>  -->
                 <class>Mycompany_Mymodule_Model</class>
            </mymodule> <!-- same chnage here -->
        </models>
    </global>

Issue2:

mymodule/model_cron is run as model which in run on cron job

magento is manupulate this it class by

mymodule= Mycompany_Mymodule_Model as i define at config xml

model_cron =Model_Cron

the final class is Mycompany_Mymodule_Model_Model_Cron it path should be

app/code/yourmodulecodepool/Mycompany/Mymodule/Model/Model/Cron.php

If you use mymodule/model_cron::editEntries in cron then this file path location

 app/code/yourmodulecodepool/Mycompany/Mymodule/Model/Observer.php

and class is

 Mycompany_Mymodule_Model_Observer

Modified config.xml

<?xml version="1.0" ?>
<config>
    <modules>
        <Mycompany_Mymodule> <!-- module should be same sa filepath -->
            <version>1.0.0</version>
        </Mycompany_Mymodule>
    </modules>

   <global>
        <models>
            <mymodule> <!--  change <Mymodule> to <mymodule>  -->
                 <class>Mycompany_Mymodule_Model</class>
            </mymodule> <!-- same chnage here -->
        </models>
    </global>

    <crontab>
        <jobs>
            <mycompany_mymodule>
                <schedule>
                    <cron_expr>* * * * *</cron_expr>
                </schedule>
                <run>
                    <model>mymodule/observer::editEntries</model>
                </run>
            </mycompany_mymodule>
        </jobs>
    </crontab>
</config>