123 Data Exporter for ACT! can be run in the background. To do that, call the executable that is built for your ACT! database with a -B flag. For example:
For ACT! 2010, Build 12.0.x: "C:\Program Files\Data Fields Exporter for ACT!\123-Data-Fields-Exporter-12.exe" "-B"
For ACT! 2010, Build 12.1.x: "C:\Program Files\Data Fields Exporter for ACT!\123-Data-Fields-Exporter-12.1.exe" "-B"
Make sure that all the settings are correct and that you have overwrite files enabled so that the software will run.