The script has the "Set Error Capture" and "Allow user to Abort steps in place.
The procedure take a long time, as the user must do several things before a response is returned to the file.
That is a system message that can't be suppressed. You might be able to shift it to "Perform Script on Server" to suppress any system dialogs but it depends on your setup and what the script does.
Usually I only see that error on large data sources I'm trying to insert from the web using the insert from URL script step. You have not provided a sample file or screenshot of your script to help us identify any further improvements.
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