[Doitsu]

I was able to reproduce the problem. It's caused by the period in the file name.
I'll try to upload a fixed version today.

Update: The plugin assumes that writer2xhtml will create an output file with the base name without an extension and .epub.

However, writer2xhtml uses this code to remove the extension:

    public static final String getFileExtension(String sURL) {
    	String sFileName = getFileName(sURL);
    	int nDot = sFileName.lastIndexOf('.');
    	if (nDot>=0) {
    		return sFileName.substring(nDot);
    	}
    	else {
    		return "";
    	}
    }

    public static final String removeExtension(String sURL) {
    	String sExt = getFileExtension(sURL);
    	return sURL.substring(0, sURL.length()-sExt.length());
    }

I don't know Java, but the code apparently generates the output file name demo 1.epub if the input file name is demo 1.4.odt instead of demo 1.4.epub. Since the plugin can't find demo 1.4.epub it assumes that the conversion has failed and returns -1.