WL solved for me but here's fix for everyone so they don't have to keep posting it ;-)

1. Your data updates aren't working. Yahoo does this periodically.
2. So you need to go to the extensions and update them BUT if you're running an old version of WL you can't update as you get the error attached. ie Error downloading extension.

Fix
1. Update your version of WL.
2. Try restarting Windows and switching to a different network connection first. I needed to do this.
3. If it won't work, please uninstall and reinstall WLD:

Users of Wealth-Lab Developer version 6.9.15 (and lower) who installed it more than a year ago WILL experience a "URI Error" message with the error text "Error when identifying Extension download URIs..." on trying to install / update an Extension OR download Strategies.

ONLY if you're affected, we recommend you perform a reinstallation (which will NOT affect your Strategies, data and preferences) to solve the problem:

1. Uninstall WLD

2. Delete these folders with all the files (but back up your custom-built DLLs if you have them)
"c:\Program Files\MS123\Wealth-Lab Developer 6"
"c:\Program Files (x86)\MS123\Wealth-Lab Developer 6"

3. Download and install the updated WLD installer(s) from our website:
https://www.wealth-lab.com/Download/

4. Reinstall all required Extensions from our website
https://www.wealth-lab.com/Extensions/Extension-Finder/

Thanks for posting this.