Hi, welcome to the forums!
You only need to compile from source if you want to use a different version of Python than the SDK build was compiled against. The 1.7.2 build is compiled against Python 2.6, while the latest development builds are compiled against Python 2.7.
You need to replace the Python installation in the thirdparty/win-python directory to build with a different Python version. Just empty that directory, run the Python 2.7 installer, and choose that directory as installation directory. Also be sure to choose “Install for this user only”, to make sure it copies python27.dll also into that directory (as opposed to the Windows system32 directory).
Then, clear the “built” directory to enforce a clean build, and run makepanda again to build it. (I need to point out that a build with --nothing actually excludes a lot of features that you will probably want, such as a renderer module, many useful utilities, and sound support. You probably want to make sure you have the thirdparty packages in the right place and choose --everything, and maybe add some --no arguments to exclude some modules you’re sure you don’t need).
Be sure to uninstall any already installed build of Panda3D before you try to build from source.