Some things I would check:
1) Check in the BIOS using a standard video card, and make sure the AGP options are set correctly, and disable any on-board video.    Then, reinstall ArcadeVGA and see if it works.
2) Try updating to the latest BIOS for your model computer
3) The ArcadeVGA card could be defective.  I would try calling Ultimarc to see if they would exchange it.
4)  Go to the tech support for your motherboard, and look up the meaning of the 8-beep code.  Be sure to note any pauses, or if any beeps are longer or a different tone than others.