If you want your piechart to show the value less than 2 % you can do it in following manner.
Inside your jqplot /plugin folder there is a file named "jqplot.pieRenderer.js". Please search for the parameter [this.dataLabelThreshold = " "] and decrease this value as per your requirement. You can set it to zero also.
But it will make the global change.
If you want to set for an individual chart, please set this parameter in that file itself.
I hope this will help you to fix the bug that you are facing.