I'll tell you what I have told others:
If the bot is entirely gray or if you can't click through it to the game window, make sure that your system is fully updated with the latest Windows updates, especially anything relating to the .Net framework. At minimum, you should have .Net 3.5 and .Net 3.5 SP1.
Additionally, disable any multi-monitor software and see if that helps. Programs like UltraMon and SplitView are notorious for causing issues with transparent windows.
Also, check to make sure your default color space has not been changed. This includes making sure your red/green/blue levels (in control panel/software, not on your physical monitor) have not been adjusted and are at their default levels. Brightness/contrast alterations are fine, but gamma is not. These kinds of adjustments alter the meaning of the transparency key for the window, so instead of gray (0x3C3C3C in hex) being transparent, it's a slightly different kind of gray. Not using 32-bit color will also cause issues with the interpretation of this gray.
If you have checked all of the above and are still having issues, then I'm not sure if there's much more I can do for you. This is working on all of my systems and I'm getting a lot of private feedback for suggestions from people who have everything from Windows 2000 all the way up to 7 (I use 7 x64 at home and XP x86 at work, myself) so it's difficult for me to really troubleshoot this since I can't see the issue myself.
That said, if there's more information I can add to troubleshooting in the future, I will let you know...