Are you running MA3D as a windows administrator? Right-click on the desktop icon and choose {Run as Administrator}, or to make it always do that, right-click, go to Properties, go to the "Compatibility" tab, check the box near the bottom that says "Run this program as a Windows administrator" (or something along those lines), Apply and Close.

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Ryan Kanarek
Technical Support
ACT Entertainment
support (at) actentertainment (dot) com