Fatal error: Class 'Modeltoolexportimport'

Hello,

Im having some issues with the import / export extension I did a manual install because I couldn't upload it via the moduler installer, I copied the files to the correct directory and it didn't show in my menu even after refreshing the modules etcs, then I went into the install.xml file and located the other files I need to edit, edited them it appear in my menu then I went to it and got the error: If anyone has an answer to this it would be really helpful.

in order to expect a reply, next time, you better alwasy inform, on, what you use,
as OC-Version, Theme, and Extensions installed. Anyting else is just a waste of time.
Ernie