It is createInstanceFromService that's failing and 5 means "ErrNoComponent - the factory does not support creating components of the specified type".
The reason it doesent say anything after the colon is because no error message is returned from that createInstanceFromService.
(Could also be that KLibLoader::self()->lastErrorMessage() is not the correct way to get the message string)

Anyway, I would think this means either the gubed plugin or desktop file isnt found. Could you do a 'updatedb && locate quantadebuggergubed' and post the results (updatedb will take some time and is not required if you do that regularly)

Also, what are your KDE paths set to?

/Linus

SVN commit 480498 by amantia:

It is a QObject, so use Q_OBJECT.
Unfortunately it doesn't solve the critical bug 116396, the debugger client is still not loaded because the dynamic_cast in KParts::ComponentFactory::createInstanceFromFactory fails.

CCBUG: 116396

 M  +1 -1      gubed/quantadebuggergubed.cpp  
 M  +2 -0      interfaces/debuggerclient.cpp  
 M  +2 -0      interfaces/debuggerclient.h  


--- branches/KDE/3.5/kdewebdev/quanta/components/debugger/gubed/quantadebuggergubed.cpp #480497:480498
@@ -43,7 +43,7 @@
 
 
 K_EXPORT_COMPONENT_FACTORY( quantadebuggergubed,
-                            KGenericFactory<QuantaDebuggerGubed>("quantadebuggergubed"))
+                            KGenericFactory<QuantaDebuggerGubed>("quantadebuggergubed"));
 
 const char QuantaDebuggerGubed::protocolversion[] = "0.0.12";
 
--- branches/KDE/3.5/kdewebdev/quanta/components/debugger/interfaces/debuggerclient.cpp #480497:480498
@@ -156,3 +156,5 @@
 {
   KMessageBox::error(NULL, i18n("%1 does not support setting the value of variables.").arg(this->getName()), i18n("Unsupported Debugger Function"));
 }
+
+#include "debuggerclient.moc"
--- branches/KDE/3.5/kdewebdev/quanta/components/debugger/interfaces/debuggerclient.h #480497:480498
@@ -62,6 +62,8 @@
 
 class DebuggerClient : public QObject
 {
+  Q_OBJECT
+
   private:
   protected:
     DebuggerClient(QObject *parent, const char* name);

I forgot to CC the bug here.

----------  Forwarded Message  ----------

Subject: branches/KDE/3.5/kdewebdev/quanta
Date: Tuesday 15 November 2005 12:48
From: Andras Mantia <amantia@kde.org>
To: kde-commits@kde.org

SVN commit 480512 by amantia:

Workaround for a failed dynamic_cast when loading a KParts-based
 plugin. Debugger plugins are now loaded and seem to work on SUSE 10 as
 well.

 M  +6 -1      components/debugger/debuggermanager.cpp
 M  +7 -1      project/projectprivate.cpp


---
 branches/KDE/3.5/kdewebdev/quanta/components/debugger/debuggermanager.
cpp #480511:480512 @@ -96,7 +96,12 @@
       if(Project::ref()->debuggerClient() == service->name())
       {
         int errCode = 0;
-        m_client =
 KParts::ComponentFactory::createInstanceFromService<DebuggerClient::De
buggerClient>(service, this, 0, QStringList(), &errCode); +//Workaround
 for dynamic_cast not working correctly on SUSE 10, gcc 4.0.2 +//The
 correct way should be a simple:
+// m_client =
 KParts::ComponentFactory::createInstanceFromService<DebuggerClient>(se
rvice, this, 0, QStringList(), &errCode); +        QObject* obj =
 KParts::ComponentFactory::createInstanceFromService<QObject>(service,
 this, 0, QStringList(), &errCode); +        if (obj &&
 obj->inherits("DebuggerClient"))
+          m_client = static_cast<DebuggerClient *>(obj);

         //kdDebug(24002) << service->name() << " (" << m_client << ")"
 << endl;

--- branches/KDE/3.5/kdewebdev/quanta/project/projectprivate.cpp
 #480511:480512 @@ -1484,8 +1484,14 @@
     KService::Ptr service = *iterDbg;
     if(m_debuggerClientEdit == service->name())
     {
+      DebuggerClient *dbg = dbg;
       int errCode = 0;
-      DebuggerClient::DebuggerClient* dbg =
 KParts::ComponentFactory::createInstanceFromService<DebuggerClient::De
buggerClient>(service, this, 0, QStringList(), &errCode); +//Workaround
 for dynamic_cast not working correctly on SUSE 10, gcc 4.0.2 +//The
 correct way should be a simple:
+// DebuggerClient *dbg =
 KParts::ComponentFactory::createInstanceFromService<DebuggerClient>(se
rvice, this, 0, QStringList(), &errCode); +      QObject* obj =
 KParts::ComponentFactory::createInstanceFromService<QObject>(service,
 this, 0, QStringList(), &errCode); +      if (obj &&
 obj->inherits("DebuggerClient"))
+        dbg = static_cast<DebuggerClient *>(obj);
       if (dbg)
       {
         QDomNode projectNode = m_sessionDom.firstChild().firstChild();

-------------------------------------------------------