Syntax error: newline unexpected - QtCreator

I want to develop some Qt applications with QtCreator IDE on Ubuntu 12.04. When I'm trying to build even the most simple project, I get this error:

/home/jerzu/QtTest/qt-test/mainwindow.ui:-1: error: 2: ../qt-test/mainwindow.ui: Syntax error: newline unexpected

And when I'm using command line (qmake2 ProjectName.pro command), everything goes well. I'm sure that the qmake path in QtCreator is correct.

Have you any idea, what's going on?

EDIT:

mainwindow.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralWidget"/>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>400</width>
     <height>25</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

output line

17:23:26: Running steps for project QtTest... 17:23:26: Configuration unchanged, skipping qmake step. 17:23:26: Starting: "/usr/bin/make" ../QtTest/mainwindow.ui -o ui_mainwindow.h ../QtTest/mainwindow.ui: 2: ../QtTest/mainwindow.ui: Syntax error: newline unexpected make: * [ui_mainwindow.h] Error 2 17:23:26: The process "/usr/bin/make" exited with code 2. Error while building/deploying project QtTest (kit: Beagle-xM2) When executing step 'Make'

EDIT2:

Makefile:

http://shrib.com/CBm2rKJV