I construct my boxplots (shown in this figure: http://img204.imageshack.us/img204/7518/boxplot2.png) using 5th, 25th, 50th, 75th, 95th percent of my data explicitly. For some reason on boxplot 3 and 5 on the figure I get fliers instead of whiskers on the lower parts.

Do you have any idea what could be the reason for this behaviour?