diff --git a/client/Makefile.am b/client/Makefile.am
index 3eb3ecb..22d7f32 100644
--- a/client/Makefile.am
+++ b/client/Makefile.am
@@ -12,7 +12,7 @@ twin_DATA = crystal.desktop
 noinst_HEADERS = crystalclient.h crystalbutton.h imageholder.h buttonimage.h tiles.h overlays.h
 
 kde_module_LTLIBRARIES = twin3_crystal.la
-twin3_crystal_la_SOURCES = crystalclient.cc myrootpixmap.cc crystalbutton.cpp \
+twin3_crystal_la_SOURCES = crystalclient.cpp myrootpixmap.cpp crystalbutton.cpp \
 	imageholder.cpp buttonimage.cpp tiles.h overlays.h
 twin3_crystal_la_LIBADD = $(kde_libraries)/libtdecorations.la $(LIB_TQT) $(LIB_TDEUI)
 twin3_crystal_la_LDFLAGS = -module $(all_libraries) $(KDE_PLUGIN) $(LIB_TQT) $(LIB_TDECORE) $(LIB_TDEUI) -ltdefx -lDCOP
diff --git a/client/config/Makefile.am b/client/config/Makefile.am
index 2b2e03c..a491211 100644
--- a/client/config/Makefile.am
+++ b/client/config/Makefile.am
@@ -7,14 +7,14 @@ INCLUDES = $(all_includes)
 noinst_HEADERS = crystalconfig.h
 
 kde_module_LTLIBRARIES = twin_crystal_config.la
-twin_crystal_config_la_SOURCES = configdialog.ui infodialog.ui crystalconfig.cc crystalconfig.h
+twin_crystal_config_la_SOURCES = configdialog.ui infodialog.ui crystalconfig.cpp crystalconfig.h
 twin_crystal_config_la_LDFLAGS = -module $(all_libraries) $(KDE_PLUGIN) $(LIB_TDECORE)
 twin_crystal_config_la_LIBADD = $(LIB_TDEUI) $(LIB_TDEIO) $(LIB_TQT)
 twin_crystal_config_la_METASOURCES = AUTO
 
 DISTCLEANFILES = $(twin_crystal_config_la_METASOURCES)
 
-crystalconfig.cc: configdialog.h infodialog.h
+crystalconfig.cpp: configdialog.h infodialog.h
 
 
 messages:
diff --git a/client/config/crystalconfig.cc b/client/config/crystalconfig.cpp
similarity index 100%
rename from client/config/crystalconfig.cc
rename to client/config/crystalconfig.cpp
diff --git a/client/crystalclient.cc b/client/crystalclient.cpp
similarity index 100%
rename from client/crystalclient.cc
rename to client/crystalclient.cpp
diff --git a/client/myrootpixmap.cc b/client/myrootpixmap.cpp
similarity index 100%
rename from client/myrootpixmap.cc
rename to client/myrootpixmap.cpp
diff --git a/pics/README b/pics/README
index 20253b8..d4eb625 100644
--- a/pics/README
+++ b/pics/README
@@ -10,7 +10,7 @@ Use with 'embedtool file1 file2 > tiles.h', or 'embedtool foo/*.png > bar.h'.
 3) A new button theme is much more work:
 - Add a directory, populate it with png images. List this directory in the ${themes} variable of the Makefile.am
 - In the top directory run: make -f Makefile.cvs. Now make should include your png images in the tiles.h, which gets included in the crystal source.
-- You have to add some logic to the ../client/crystalclient.cc and ../client/config/configdialog.ui file, to really make your button theme available.
+- You have to add some logic to the ../client/crystalclient.cpp and ../client/config/configdialog.ui file, to really make your button theme available.