You have to have some kind of social problems, but when people think of them they think about someone who can't carry a conversation or talks inappropriately or something in those terms. Many aspies have learned the rules of communication quite mechanically (sometimes not even knowing all people don't do it like that), so socializing can go fine but be draining. Some are quite good at reading social cues and facial expressions but it takes a lot of energy since they use a bottom-up rather than top-down process.

Also, some aspies have issues in that they are simply uninterested in others. Which might just come across as being a loner.

Just to toss in some confusion, it does seem like aspies with ADD have better social skills than aspies without. It sounds very counterintuitive, but it might be that those with ADD are more spontaneous and impulsive which might make up for the lack of flow in communication common in Asperger's, or that those with ADD have more practice with social skills simply because they are more impulsive talkers, run into more misunderstandings and just get more practice.