I believe we're "talking past each other" and you're making this harder on yourself than it need be. I will step by step you through downloading and installing the OCR add-on. The following presumes that NVDA is already running and will stay so throughout the process.
- Navigate to the NVDA community add-ons page, find the OCR add-on link, and click it to get to that add-on webpage.
- On the OCR add-on web page, there is a download link for the latest version of the add-on, at this point in time that's version 0.20120529.01. Click on that link.
- When the Save As dialog comes up, navigate to wherever you wish to save the add-on file. I saved mine to desktop. (The OCR add-on is about 70 MB in size and takes a while to complete downloading).
- Open the folder where you saved the add-on file by whatever technique you prefer and select the add-on file you downloaded.
- Hit Enter. A dialog from NVDA comes up asking if you're really sure you want to install the add-on. Hit the Yes button.
- Wait for the installing add-on progress dialog to complete. NVDA will then pop up a dialog stating that the add-on has been installed and must be restarted to take effect and asking if you'd like to restart now. Hit the Yes button. You will then hear the NVDA shutting down chimes followed immediately by the NVDA starting up chimes.
- NVDA now has the add-on installed and ready for use.
If you wish to verify that OCR is installed bring up the NVDA context menu, choose Tools, then choose Manage Add-Ons. You will be presented with a dialog listing all the add-ons you have installed and OCR should be in that list.