The failure in Net Express when no $ is present is because, according to step/rule #3 in the File Handler's file mapping process, the check is for an environment variable named dd_CNV. You have just CNV, which is the environment variable name checked according to rule #4. We are using the "dd_" form for ALL of our environment variable names.
Please change the environment variable names to dd_CNV in both projects, remove the $ from both programs, and try it again.