diff -Nur qcad-2.0.4.0-1.src-orig/qcad/src/qc_applicationwindow.cpp qcad-2.0.4.0-1.src/qcad/src/qc_applicationwindow.cpp
--- qcad-2.0.4.0-1.src-orig/qcad/src/qc_applicationwindow.cpp	2004-09-14 22:13:07.000000000 +0200
+++ qcad-2.0.4.0-1.src/qcad/src/qc_applicationwindow.cpp	2005-02-14 23:13:42.569182424 +0100
@@ -2774,11 +2774,19 @@
 #if QT_VERSION>=0x030200 
         assistant->setArguments(args);
 #endif
+        connect( assistant, SIGNAL(error(const QString&)), this, SLOT(slotAssistantError(const QString&)) );
     }
     assistant->openAssistant();
     //assistant->showPage("index.html");
 }
 
+void QC_ApplicationWindow::slotAssistantError(const QString& msg) {
+    QString tmpMsg = msg;
+    if ( !assistant->isOpen() ) {
+        tmpMsg += "\n\nIf Qt Assistant is missing, you need to install the qt-devel package.";
+    }
+    QMessageBox::warning( this, QC_APPNAME, tmpMsg );
+}
 
 
 /**
diff -Nur qcad-2.0.4.0-1.src-orig/qcad/src/qc_applicationwindow.h qcad-2.0.4.0-1.src/qcad/src/qc_applicationwindow.h
--- qcad-2.0.4.0-1.src-orig/qcad/src/qc_applicationwindow.h	2004-09-14 22:13:07.000000000 +0200
+++ qcad-2.0.4.0-1.src/qcad/src/qc_applicationwindow.h	2005-02-14 23:03:46.000000000 +0100
@@ -224,6 +224,8 @@
     /** resizes window to 640x480 for screen shots */
     void slotTestResize1024();
 
+    void slotAssistantError(const QString&);
+
 signals:
     void gridChanged(bool on);
     void draftChanged(bool on);