Nobody is as reckless as Mark Foley was with the e-mails and IM's without someone knowing about it. That's the way the world works.
That Hastert was notified was reported earlier in the day and Alexander (R) is the one who informed Hastert. It was also reported earlier that pages were told to watch out for Foley.
My comment that you quoted was specifically related to the report that this is part of some big Republican cover-up. There is absolutely no proof of that outside what one page has said.