What I learned in business school was that most young companies fail from accounting issues. Taxes, filing, etc. You the founder know the tech, but the bookkeeping sinks you.

This may not apply to startups where you're being funded by speculators (that IS what Venture Capitalists are).

I've been both successful with my first company and unsuccessful with my second (while retaining the first) and saw these issues first hand. My companies were self-funded, not with speculator money, so again my experience and university knowledge may not apply in the case of "start-ups" (i.e. speculator funded companies).