it basiclly means they have 2 different sets of XDCC lists...so you need to specify which one you are trying to request by using the name of that pool of files
most ppl have ads like this that specify their different pools,but not all:
-RSG- [XDCC active] You have access to the following pools: Cabbit, DMG. Use: /ctcp RSG XDCC LIST <poolname> to list XDCC Files for one XDCC pool. - SysReset 2.51
not sure if that helped with your situation but at least you know what is means now