CVS stores the login and password information in a file called ".cvspass". Normally CVS loads this file in your home directory, but if you want to have Hudson load it from a different place, specify the full path to the file. Otherwise leave it blank.
If you are using CVSNT (am I?), then this setting is likely to be ignored. See this note for more about why. In this case, you need to run "cvs login" command manually to enter password. If Hudson runs under the same user as you do, then this would be straight-forward. However, if Hudson runs as a service, you'd need to first launch `CMD.exe` as the SYSTEM user, then you need to run cvs command from there. See this document for how to do this.