You have opened the component in QTP and done some updates in script and forgot to save the component...! ;)
Now, on your system logged into QC and try to execute some scripted components...! could you able to execute the component successfully?
QC will try to open the scripted component in QTP in read only mode and run the component. But, QTP contains someother script which hasn't saved yet... so, it will show you the details about unsaved document (component script) on QTP in QC dialog box.