This is a problem that's been driving me crazy on this site. I have tested the site extensively and about 5% of the time, under firefox, clicking on a link within this forum will result in an empty php document.
The same behavior does not occur while using IE.
On several occassions I have lost entire replies due to this bug. It's good to see someone else point it out. As stated the behavior only occurs with firefox. I have tried it without my extensions installed and I even updated the browser to see if it would relieve this error.
Apparently, on OSX something different happens. On windows it just goes to a blank php document. I guess on OSX it depends on how you have your download settings configured.