this is what i get when i try to open it
I did nothing but downloading the mumble.1.2.3a, running it, and when i'm opening the software its not working
Have you tried running it as an Admin? If not, right click on the shortcut, go to properties, click the "Compatibility" tab, look at the bottom for the "Privilege Level" and check the box next to "Run this program as an administrator".
If that is of no help to you, you might check your Windows Security settings to see if it's allowing Mumble to be opened on your computer.