Well, I hope you didn't forget to check how the applet worked, running it on your computer's hard drive. If it's running OK you can upload your files to the server.
You can upload files any way you like, but you need to be sure in the following...
1. You MUST upload the files in binary mode.
2. You MUST not change or convert filenames for class files.
3. You MUST upload all classes. Do not forget that the applet class can call other classes, so upload all .class files which were in the unzipped package.
4. Read the previous page !
If you use WsFTP or other similar FTP programs, you need to be sure that the FTP program supports long file names, and be sure not to convert it to uppercase or lowercase. For some FTP programs, you need to force ftping in binary mode.
If you use the EZUpload utility at Geocities, verify that both "Convert" checkboxes are not checked.
I hope that these brief instructions will help you to avoid most problems.
Here is a Troubleshooting
guide