http://latimesblogs.latimes.com/washington/2008/07/ron-paul-bob-ba.html
I'm very certain this is just a "back off" thing and nothing more. Yes, we donated 1,050,000 to Paul's congressional campaign. Yes he spent most of it. And yes, he beat Peden and has no opponents in November. The thing is though, this money doesn't have to be spent now, it can be spent on any future campaigns.
So with Peden already talking about running again in 2010, I think Paul wanted to do something to stop him and anyone else thinking about it dead in their tracks. No one sane is going to waste money on a filing fee to take on a popular incumbent like Paul....with over 3.5 million to defend his House seat. It'd be a huge waste of time and money for any republican, democrat or libertarian. Just ask Chris Peden, he spent 150,000 dollars of his own money trying to beat Paul in the March 4, 2008 TX-14 republican primary...and he lost by over forty percentage points.
Also, if Paul ever feels frisky, he can use that massive amount of campaign cash for a U.S. Senate or Governor's run in Texas.