Willingness to learn and pick up skills. Not the technical ones - your co-founder has that in order. I'm talking about:
Sales
Marketing
Fundraising
How to talk to a lawyer
Figuring out what business licenses you need and how to maintain them
Accounting
Interpreting from Geek to English
Hiring to fill the gaps in your knowledge (and firing those who don't)
Contract negotiation
Identifying niches for business opportunities
Basically, anything involved in creating a business which doesn't involve technology; there's quite a few of these, and in many ways they are as or more important to the success of the business than technical knowledge. Even if you create the perfect product, you still need someone to market and sell it to the masses.
Sales
Marketing
Fundraising
How to talk to a lawyer
Figuring out what business licenses you need and how to maintain them
Accounting
Interpreting from Geek to English
Hiring to fill the gaps in your knowledge (and firing those who don't)
Contract negotiation
Identifying niches for business opportunities
Basically, anything involved in creating a business which doesn't involve technology; there's quite a few of these, and in many ways they are as or more important to the success of the business than technical knowledge. Even if you create the perfect product, you still need someone to market and sell it to the masses.