Sounds pretty clear, there is something in one or more variables in the input data that is invalid.
With a message about characters I would suggest running proc freq on any of the character variables used in the model to see what might be consider invalid.
Note: ANY discussion of ERRORS should include 1) the LOG showing the code and all messages and 2) best would be to provide and example of data in the form of a working data step.
The code is to head off all of the questions about variable type use, role in the model, dependent, independent, as well as options that may not interact well with each other. All of the messages are important because of the times SAS reports a problem and use of an alternate option in an attempt to get some result. The example data clarifies variable types and will help someone suggest which variables need to be looked at for likely problems.