Solution
First, verify that the error is caused by your custom device by determining that the error does not persist after removing your custom device from your system definition.
If you are deploying to an RT target, attempt local deployment on your Windows PC. If this deployment is successful, start looking for VIs that are incompatible with RT systems within the custom device as they may be blocking successful deployment.
Next, verify that this error occurs while deploying your system definition file to the target. If you are seeing this error, you should investigate the Initialization phase of your RT Driver. This would include the
Initialization and
Start cases of an inline hardware or inline model custom device and anything prior to the Report Final Status VI of an asynchronous custom device:

In addition, any
Action VIs that you have configured to run on download or on compile could also cause a deployment error.
If you are seeing deployment errors, check the
Console Viewer or the
Web Interface to view error information and determine the state of the VeriStand engine. If you are unsure that your changes are being propagated to the target, you can try deleting and re-adding the custom device folder on your RT target. These files are found at
c:\ni-rt\VeriStand\Custom Devices
on Pharlap and VxWorks targets and at
c:\ni-rt\NIVeriStand\Custom Devices
on Linux RT targets.