If a firm has 100 million in revenues Does that mean it has generated a cash flow of 100 million?

Not necessarily. Let's say a company sold services on December 20th, 2009 for $50 million. If they sold these services on account, the journal entry would be:

Accounts Receivable $50 million

Service Revenues $50 million

This company would have $50 million in Revenues but $0 in cash flow for 2009.

If they payment is received in 2010, it would look like this:

Cash $50 million

Accounts Receivable $50 million.

Here they would have (if this is their only entry) $50 million of cash flow and $0 of revenue.

It is the difference between cash and accrual basis accounting.