You're either missing the helper definition in config.xml:

<config> ... <global> ... <helpers> <ddevs_ebayaff> <class>Ddevs_Ebayaff_Helper</class> </ddevs_ebayaff> </helpers> ...

or should add module="example" to adminhtml.xml, the <sub_menu1 translate="title" > node

<sub_menu1 translate="title" module="example" >

/Edit: As a best practice, if you're using a translate attribute, you should also define a module default helper.

Cheers

You are either missing the helper definition in config.xml:

<config>
  ...
  <global>
    ...
    <helpers>
      <ddevs_ebayaff>
        <class>Ddevs_Ebayaff_Helper</class>
      </ddevs_ebayaff>
    </helpers>
    ...

or should add module="example" to adminhtml.xml, the <sub_menu1 translate="title" > node

<sub_menu1 translate="title" module="example" >

##Edit

As a best practice, if you're using a translate attribute, you should also define a module default helper.