Team work and interpersonal skills are absolutely essential for the present day knowledge worker (software developers, and the like). If you don't like working in teams, don't know how to work in a team, then you may not be able to find work.

In the larger software community, most agree that:

programming is a social activity, ... being the lone wolf ... is not what we do anymore  - Douglas Crockford  

And most of us have come to understand that:

Team dynamics; how well a team works together has a bigger impact on a project than the developer’s individual capabilities. And that: No individual is a success who hurts the team, and no individual is a failure who helps it.- Software Project Survival Guide

So, it should come as no surprise when a company (like Microsoft) that depends almost entirely on team work lists Team working and interpersonal skills as the VERY most important business skill. - Computer knowledge 'undervalued'

However; it's often hard for the those in management to understand that you can't force people into a team environment - let alone change or mold them. So, if someone doesn't like working on teams, has never worked on a team, or doesn't agree with your existing team's cultural views, then you should ask why. Because:

the people that work for you through whatever period will be more or less the same at the end as they were at the beginning.  If they're not right for the job from the start, they never will be. - Peopleware: Productive Projects and Teams

In reality, we have very little influence on our team members, poorly matched cultural values will likely result in poorly functioning teams, which in turn negatively results the projects success. Joel Spolsky takes this train of thought a little further and suggests that:

it is much, much better to reject a good candidate than to accept a bad candidate. A bad candidate will cost a lot of money and effort - The Guerrilla Guide to Interviewing (version 3.0)

However; most organizations don't have the exposure that Spolsky does, and can hardly find candidates period - let alone the very best candidates. Often in the real world, the only chance you'll have to guide (influence) any team of developers (or anyone), is to lead by example. Jeff Atwood offers some great advice: 

Cajoling and berating your coworkers into compliance isn't an effective motivational technique for software developers, at least not in my experience. If you want to pull your team up to a higher level of engineering, you need a leader, not an enforcer. The goal isn't to brainwash everyone you work with, but to negotiate ...

So much of leadership is learning to give a damn about other people, something that us programmers are notoriously bad at. We may love our machines and our code, but our teammates prove much more complicated. - Leading by Example

Team work and interpersonal skills are more important than technical skills. The ability to work in a team is absolutely mandatory for today's software developer.