Failed build docs

When trying to build docs with "mingw32-make docs" I got error:

c:/QtSDK/Qt64-5.0.0/bin/qmake.exe CONFIG+=release -o Makefile ../../../src/qbs/qbs.pro
SRCDIR=C:/QtSDK/Qt-builds/src/qbs/doc OUTDIR=C:/QtSDK/Qt-builds/work/build-x64/qbs-5.0.0/doc/html QTC_VERSION=0.3.0 QTC_VERSION_TAG=030 c:/QtSDK/Qt64-5.0.0/bin/qdoc C:/QtSDK/Qt-builds/src/qbs/doc/qbs.qdocconf
In file included from C:/QtSDK/Qt-builds/src/qbs/doc/config/qt-html-templates.qdocconf:1,
C:/QtSDK/Qt-builds/src/qbs/doc/qbs.qdocconf:3:
C:/QtSDK/Qt-builds/src/qbs/doc/config/qt-html-default-styles.qdocconf:7: warning: File 'C:/QtSDK/Qt-builds/src/qbs/doc/config/style/offline.css' does not exist
C:/QtSDK/Qt-builds/src/qbs/doc/items/product.qdoc:53: warning: '\o' is deprecated. Use '\li'
C:/QtSDK/Qt-builds/src/qbs/doc/items/product.qdoc:54: warning: '\o' is deprecated. Use '\li'
C:/QtSDK/Qt-builds/src/qbs/doc/items/product.qdoc:55: warning: '\o' is deprecated. Use '\li'
C:/QtSDK/Qt-builds/src/qbs/doc/items/product.qdoc:56: warning: '\o' is deprecated. Use '\li'
c:/QtSDK/Qt64-5.0.0/bin/qhelpgenerator -o "C:/QtSDK/Qt-builds/work/build-x64/qbs-5.0.0/doc/qbs.qch" C:/QtSDK/Qt-builds/work/build-x64/qbs-5.0.0/doc/html/qbs.qhp
Missing Qt help project file.

Usage:

qhelpgenerator <help-project-file> [options]

-o <compressed-file> Generates a Qt compressed help
file called <compressed-file>.
If this option is not specified
a default name will be used.
-c Checks whether all links in HTML files
point to files in this help project.
-v Displays the version of
qhelpgenerator.

makefile:379: recipe for target 'qch_docs' failed
mingw32-make: *** [qch_docs] Error -1