For example, trying to use: "FOO=C:\Foo" will result in a "FOO=C" and "BAR=http://someplace.com" will result in "BAR=http".

The software does not detect these issue, and contains no immediately apparent way to escape the character (such as using two colons in a row, nor trying to place quotes around the value). The help texts should instruct the user how to escape colons too, once it is possible.