I fought with this error yesterday.
My problem was resolved by copying a new version of the acuconfig.exe file over to the computer. The first copy of the file didn't maintain the digital signature of the file.
I could see if it was going to fail by right clicking on the acuconfig.exe file and going to properties. If the digital signatures tab was missing, that copy of the file would never work. I copied over a new version, checked the properties, and then the digital signatures tab was there. This error went away as long as the acuconfig.exe file had the digital signatures tab.