Please don't take this question the wrong way... No harm is meant by asking it... but it must be asked.
Are your friends trying to log onto accounts that WGT have disabled due to them being 'multiples'? Once they (WGT) find a multiple account they disable it... the name stays on the roster but the account can not be accessed by anyone except WGT Admin personnel.
If that is not the case, then have each of them submit an email to members@worldgolftour.com to find out what has happened to their accounts.
I really hope they are not 2nd, 3rd, or 4th accounts....
Peace.