QWT Installation

Hello
I am trying to install QWT library for qt and there occurs a problem i cant solve on my own. Operating system - Windows 7.

Message from MinGW for Desktop:
1 mingw32-make[1]: Entering directory 'c:/qwt-6.1.3/designer'
2 compiling qwt_designer_plugin.cpp
3 /usr/bin/sh: /c/Qt/Tools/mingw530_32/bin/g++: Invalid argument
4 Makefile:892: recipe for target 'qwt_designer_plugin.o' failed
5 mingw32-make[1]: *** [qwt_designer_plugin.o] Error 126
6 mingw32-make[1]: Leaving directory 'c:/qwt-6.1.3/designe r'
7 Makefile:173: recipe for target 'sub-designer-make_first-ordered' failed
8 mingw32-make: *** [sub-designer-make_first-ordered] Error 2

Looks like it starts execution of Makefile for designer in qwt directory and can't execute it properly because of string "/c/Qt/Tools/mingw530_32/bin/g++"
I opened this makefile with my notepad but didn't find such string.
1) Which arguments are invalid?
2) How can i solve this and finish installation of QWT?

Thanks for reading