It sounds like you haven't used EP-Launch to
"find" the programs it needs.
If you go to View Options, select the Reset option. Then the top
button is a "Auto Find all file viewers".
that will associate (at minimum) notepad with the text viewer
option. If you have your own text viewer (such as Wordpad -- as
notepad may be limited in how much it can view), you can just select the
text editor option and browse to the one of your choice.
I believe this is probably described in the EP-Launch section of the
Auxiliary programs document but I will copy the explanation to the
Getting Started document as well for future releases.
Please try to remember to change the subject line of a reply if you're
introducing a new topic.