Now install the PC/3270 Corrective Service Diskette(s).
You will get a pop-up telling you that the CSD will replace files in the C:\PC3270W\ directory, select OK to continue the update.
When the CSD installation is complete you will get a pop-up telling you that it is complete, select OK.
Be sure to read the README.TXT file on the CSD diskette. It will have additional information about the corrective service that might apply to your installation.