Investing While in Debt
by Andrew Beattie
To become a successful investor, you have to make sure that your personal finances are in order first. Investing without a purpose is bad, but investing when you have high-interest debt is much worse. If you are drowning in overdue bills and credit card payments that you can't meet, take care of those more serious problems before getting too deep into investing.
Source: http://www.investopedia.com/articles/basics/07/10commandments.asp