it won't work as you're trying to access a string from a different process space which doesn't map to the same address in your C# app and so you just get a blank string (or an exception in some cases).
if you can do c/c++ then
https://sourceforge.net/projects/winampminimagic/ may help (need to find the time to release a pre-compiled version of that code) which would allow what you're trying to do.
-daz