why is there is a limit of number in lunching clientless ibot/ribot

i would like to know ..why is there is a limit of number in lunching clientless ibot/ribot?..sometimes i can launch 9 clientless and sometimes i can launch 10 clientless.. is there a problem with my pc physical memory or RAM?:confused:

the same with me... i got error something after launching the last bot.. it limit my number of ribots