Magento 1.8 - Class 'Mage_Helloworld_Helper_Data' not found

Question

I can't access System -> Configuration in the backend anymore. I get the message Class 'Mage_Helloworld_Helper_Data' not found.

How can I debug this, I am new to magento.

---

I found a Module named "HelloWorld" in app/code/local/Webkochshop.

This is the snippet where the helper is at:

<global>
    <helpers>
        <Webkochshop_HelloWorld>
            <class>Webkochshop_HelloWorld_Helper</class>
        </Webkochshop_HelloWorld>
    </helpers>
</global>

Answer 1

Try this:

<global>
    <helpers>
        <Webkochshop_HelloWorld>
            <class>Webkochshop_HelloWorld_Helper</class>
        </Webkochshop_HelloWorld>
    </helpers>
</global>

Webkochshop_HelloWorld should in module="Webkochshop_HelloWorld" OR change as per system config module="helloworld" in:

<global>
        <helpers>
            <helloworld>
                <class>Webkochshop_HelloWorld_Helper</class>
            </helloworld>
        </helpers>
    </global>

Answer 2

I had to change my code to this:

<global>
    <helpers>
        <helloworld>
            <class>Webkochshop_HelloWorld_Helper</class>
        </helloworld>
    </helpers>
</global>

helloworld is the module name in lower case letters.