FTPClient - Java, upload file

Question

I'm trying to do a VERY simple file upload. I want a Java FTPClient that can upload any file I tell it to. But the pdf always gets all messed up and my pdf editor (Adobe) won't open it, saying there is an I/O error.

I'm using the following class:

    import org.apache.commons.net.ftp.FTPClient;
    ....

    FTPClient client = new FTPClient();
    FileInputStream fis = null;

    try {
        client.connect("mydomain.com");
        client.login("user", "password");

        String filename = "myPDF.pdf";
        fis = new FileInputStream(filename);

        client.storeFile("temp.pdf", fis);
        fis.close();
        client.logout();
    } catch (IOException e) {
        e.printStackTrace();
    }

Why doesn't this work, and how do I fix it?