"Create a collection of documents from data"

I have tried using "Data to Documents" to convert a file into a collection of documents so I can do some text mining.  The operator successfully creates a collection of documents if used by itself.  When I connect other operators that are supposed to accept documents such as "Tokenize" I get an error that states, "Expected Document but recieved IOObjectCollection."  Is this a bug or am I doing something wrong?

Thanks,
Toby