Do you have an NVIDIA graphics card? If so, go to the nvidia display control panel, go to the Adjust Image Settings with Preview and move the slider to "Quality" preset. Alternatively, enable antialiasing in nvidia display control panel. This is by no means a "Metal Venture" issue, but a "Game Maker 7" issue, I went through a lot of pain in order to determine the source of this graphical glitch, and then a few expert members at the Game Maker community told me what this was al about.