Thread: Subclassing

I'm working on a small gui project and I needed to subclass a form. Everything looks ok but when I go and compile I'm getting the following error
In function `AMainWindow::AMainWindow(QWidget *, char const *, unsigned int)':
.obj/amainwindow.o(.text+0xb1): undefined reference to `AWorkspace virtual table'

The subclass is called AWorkspace. Any pointers (no pun intended) in the right direction would be great.

Thanks

#ifndef AWORKSPACE_H
#define AWORKSPACE_H

#include <qworkspace.h>

class AWorkspace : public QWorkspace
{
Q_OBJECT
public:
AWorkspace(QWidget *parent = 0, const char *name = 0) : QWorkspace(parent,name) {}

~AWorkspace() {}
protected:
void childEvent(QChildEvent *e);
};

#endif //AWORKSPACE_H

This is all that there is. The errors that I was talking about simply came when I tried to create an instance of this class. The childEvent function is virtual in the base class. I also tried this with just the constructor and destructor and was running into the same issues.