The other post was in an incorrect topic (SECURITY WARNINGS & Notices topic) so is right to have moved it as was suggested in the other topic.
You don’t mention what version of firefox you are using ?
The reason I mention this is that I don’t think IE Tab is supported in the latest firefox version.
The additional problem is that if you don’t have the latest version of IE installed then IE Tab which uses the IE browser engine within the firefox tab, you are vulnerable to all the vulnerabilities of IE.
What IE version do you have installed ?