DAQmx Error -200428 occurred at Write Dig Chan.vi

Hello,

I am trying to read the task name, channel name, and physical channel from a configuration file and using this information create a DAQmx task and two global virtual channels. Everything seems to be working ok (no error) until I am trying to write to one of the channels, then I get an "Error -200428 occurred at Write Dig Chan.vi". What am I doing wrong? Thanks for your help.

Peter