All of the studies on MindSwarms have a limited number of spaces for each demographic/psychographic segment. For example, the client may want 10 people to respond and request that 7 of them be women and 5 of them be daytime television watchers. Due to the fact that people who are accepted to a study often do not respond (we guess this is a result of busy schedules, travel, or other life events) we always accept more people to a study than we need.
Unfortunately, that means that sometimes a study can be closed to your segment before you get a change to respond. When that happens you get an error.
We realize that this is frustrating (and annoying), and we are trying to work on an improvement to our system so that you are at least notified when your segment is closed. If you have any ideas about how we could better handle this process, we would love to hear them--we realize we have work to do in solving this problem. You can email us or post a question in this topic thread and we will get back to you.