Bitdefender Av 2009 - File Zone Monitor Only Shows Red X

For the last couple of days, my File Zone file scan activity monitor only shows a red X, no file activity. In the past, all I had to do was reboot my computer and the File Zone would return to normal, once again showing the product scan activity, but a reboot makes no difference this time. I have removed the check from the box next to the "Enable Scan Activity bar" in settings and re-enabled it to see if this would reset it, but the red X remains. Any ideas as to what I need to do to correct this problem? I did do a search but couldn't find anything relating to my problem.

My OS is Vista 64 Ultimate, but I don't believe the problem is OS related as Vista & Bitdefender have coexisted on my system with no problems for over a year.

Any help would be much appreciated.