Arduino + Dual H Bridge + Servo

I'm using L298 Dual H-Bridge Motor Driver to drive 4 motors, which works fine. But as soon as I attach a servo to any PWM out pin

pan.attach(10)

Where pan is a servo object, two motors, i.e. one side of the dual H bridge stops working.

I'm using arduino Dumilanova.

Can someone please tell me what is going wrong and a possible workaround?

But as soon as I attach a servo to any PWM out pin

The obvious solution, then, is to not attach the servo to a PWM pin. Servos are not driven using PWM, so attaching them to PWM pins is not necessary.

Of course, as Richard points out, we need more information.