How to extract .tar.gz file : I want to extract an archive named kdiff3.tar.gz.

Using tar -xzvf filename.tar.gz doesn't extract the file. it is gives this error:

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error exit delayed from previous errors

file kdiff3.tar.gz gives this message:

kdiff3.tar.gz: HTML document, ASCII text


It would be great, if someone could help.
