adblock verification didn't work_Solved

Problem: adblock extension couldn't be installed because of Startcon verification failure:
Error: message: Signing could not be verified. -260.

This is essentially the solution:

ENABLE THE VERFICATION ON CERTIFICATE

1. Start Firefox (if it isn’t already). This assumes FireFox version 3+ so menu item names below may differ for other FireFox versions but you should be able to browse to something that has a list of certificates (See image below).
2. Go to Edit -> Preferences. New panel appears.
3. On the new panel, click Advanced category followed by the Encryption tab then View Certificates button.
4. Browse down to VeriSign certificates. You may see something similar to the below:
   
5. Notice in the above image the highlighted certificate "Verisign Class 3 Public Primary Certification Authority" I’ve chosen. It matches exactly what we got highlighted in orange earlier in step 6 from first part above.
6. Click Edit on the highlighted. You should be presented with three choices:
   This certificate can identify web sites.
   This certificate can identify mail users.
   This certificate can identify software makers.
7. Check off "This certificate can identify software makers."
8. Click Ok to save then Ok on other open panels or Save as the case may be and restart FireFox.
9. Try to download your extension again. The error should be gone.
10. You’re done!

Where I found this this was described as a solution for a problem installing a google extension
There Verisign was the verificator.
But which is the verifier for Adblock?
Here I found the answer : StartCom. everywhere you read Verisisgn replace it by Start.com and youŕe done.