Hello, Please pardon the intrusion; but I had the same problem, with the same error message. (That's how I found this thread with the forum's search engine.) I am setting up an off-lease HP business desktop pc (XP Pro OS) that I just purchased as a replacement for the grandkids machine. I had installed the "Avast!" free antivirus program and had set mbam.exe as an exemption to try to fix the problem. The update still didn't work. (I received similar results with updating the "SuperAntiSpyware" program that I also installed to see if it would update.) I had incorrectly assumed that, since I didn't activate the CA Internet Security (that was pre-installed), it was not working. I was wrong. I just now uninstalled it (through Control Panel), and after rebooting the computer both Malwarebytes and SuperAntiSpyware updated just fine, with no error messages. As a bonus, the computer is working 100 times faster than it was with the CA anti-virus software installed. Thanks Malwarebytes forum for the ideas! Good Computing to You All! Wuds