Vista Paint on Win7 OS acting strange

[Baegal]

So, I just recently (like 20 minutes ago) got Vista Paint on Windows 7 (something about taking ownership of files and replacing etc. etc.) with the help of this website.
One of the main reasons I wanted to revert back to vista paint is because windows 7 paint is glitchy when it comes to the right click eraser recolor trick (it'll select only a few pixels of the color, or none at all), and when it comes to making the secondary color transparent for movement (again, only a few pixels become transparent or none at all).

I was able to open up vista paint fine, and decided to try the recoloring thing out. For some odd reason, recoloring and movement works perfectly fine on new documents, but when I open up an already existing file (one I made on win7 paint), it doesn't work. Nothing becomes transparent, and nothing recolored.
Does it have something to do with the file being created on windows 7 paint? I have no idea about how any of this works.

Has this happened to anyone else before? Does anyone know how to fix this? Thanks in advance.