If you wish to use the epstopdf package with Texifier, you must first enable the -shell-escape option of the typesetting pane of the Preferences window.
This is because epstopdf launches an external binary via \write18{}, which must be explicitly enabled when invoking TeX. This is because \write18{} allows for arbitrary code execution on your machine, which is a serious security hole. For obvious reasons we do not enable this by default.