This is an issue with Chrome, not AdBlock. We found a few possible solutions to this error after an extensive search. Please try them in order, installing AdBlock after each step. Only proceed to the next step if you're still getting the error.


Make sure you are logged in to the Chrome Web Store when you try to install AdBlock. (From this post on the Google Chrome forum)


Empty the Recycle Bin. (From this post on a computer repair blog)


Pause your antivirus program, if you use one. (And of course you are using one. :)


Empty your Temp directory, located in %temp% or %USERPROFILE%\AppData\Local\Temp\

(Thanks for that suggestion, Joe!)


Create a new Default folder for Chrome's extension files. Follow the instructions in this YouTube video. (From this post in the Chromium bugs forum)


Follow these Chrome troubleshooting steps.