Unable to clean...but was it blocked?

Hi All,
I just visited a website and got a red warning popup from ESET.
I had a look in the Log and it has this entry:

JS/Iframe.DA trojan unable to clean Threat was detected upon access to web by the application: W:\Program Files\Mozilla Firefox\firefox.exe.

Does that mean that there was an infection that couldn't be prevented?
Or did ESET block it and no further action is required?

Nothing's actually happened out of the ordinary but I've had this happen before and don't know wether I should be doing anything (other than avoiding the site I went to).
Thanks.
C

 

This JS/iframe.DA trojan is a threat that exists in the HTML code of the website that you were attempting to visit, and is most likely not on your computer.

The ESET antivirus HTTP checking can detect these types of threats, and prevent you from accessing these malicious webpages.

To delete all traces of the webpages from your computer will need to empty your web browser's temporary file cache.