Need advices on solving compile time errors.

[lucky6969b]

Thanks eri, I asked back the original author, he said it wasn't needed anymore, so I just don't bother fiddling with it now.
Let's go to another question, (should I open a new thread?)
is that when I enclose certain things in a namespace say

 namespace Util {
std::string compress(const std::string& input) { //throw (SaveState::Error)
	if (input.empty())
		return input;

	const uLong bufferSize = ::compressBound(input.size());

	std::string output;
	output.resize(bufferSize);

Error 1 error C2039: members of the 'compressBound': '`global the namespace'' e: \ the dosbox_ykhwong \ src \ save_state.cpp 66 1 dosbox
Error 2 error C3861: the 'compressBound': identifier not found e: \ dosbox_ykhwong \ src \ save_state.cpp 66 1 dosbox

the ::compressBound is not recognized. Is it supposed to be within Util or the global namespace.
If you have already used that before, it is called the zlib, it is also very common in IT industry. Just some compression stuff.
I am compiling the ykhwong build of dosbox.
Thanks
Jack