I noticed many people were having problems with either the Twitter or Facebook Applications and them not working.
I believe I've found out why they return a blank white page - because if you're trying to run them on an SSL site - like mine, they break SSL and thus get blocked by the browser. This is quite shocking really and I can't fathom as to why this wasn't seen or corrected earlier. I changed all HTTP links in the .php files to HTTPS and I can confirm mine now work. But to whom ever is developing these applications - this needs to be addressed immediately as it poses quite the security risk.
"//www.domain.tld" is all that's really required to maintain compatibility between SSL and non SSL sites. I implore whoever developed it to look into it.