I like this message very much, ohh! what's pitiful! it's 2 years ago. but I really hope the writer or someone can send VS51.exe. thanks!
My email zeeman2003@hotmail.com
For C, you don't have much problem with scope.
It is quite trivial to do a search/replace within a single function as long as new variables aren't created in nested blocks.
For C++ with namespaces and classes, it can often be an idea to change the variable name to something really silly, like 'xx1253beep' and catch all compilation errors. Then it will be possible to do a global search/replace to the final name. This makes sure that a missed rename of a variable doesn't gets resolved by a global variable with the same name.
Giving all global variables a prefix can also often help out.