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