Unable to load IE (IE7) extension

Sometimes Silktest2006R2 is throwing following error.

*** Error: Unable to load extensions: Enabled extension(s) for iexplore.exe#7 not installed: ActiveX, Accessibility

But Internet Explorer7 exists on that system and earlier Silktest was working fine with IE7. Even restarting Silktest will not be helpful. I didn't try restarting machine.

Problem Cause:
Browser might be running for a long time. Silktest Agent initialization used to fail.

Solution:

1. Verify your default browser.
2. Create a new Silktest project and try to enable extension for IE7. Assume that successfully IE7 extension is set for the new project. Now open your old project and try to identify any browser object. IE7 extension will be enabled automatically.

Hope that it will be a useful tips.