What version is your PS?
What Platform and OS Version?
Are you seeing these 4 icons in your Libraries Panel?
Good training video on Libraries here... http://tv.adobe.com/watch/learn-photoshop-cc/use-design-libraries/
I'm assuming you didn't want Myriad Pro. If you are using an existing Library, it may have had Myriad Pro in it at one point and is somehow corrupted.
Create a new Library, call it Test and delete it after using it, put a type asset in the library, open a new document and drag that type to the new document as a test.
Deleting the Library and creating a new one fixed the problem. You were right it must have been corrupted. Thank you!
Good, it works like advertized.
Please mark my answer CORRECT if you will.