The version of wbopendata that supports multiple indicator downloads should be version 12 from 31jan2013.
If you are using the specified version then try the below example to download the series of indicators,
wbopendata, indicator(si.pov.dday; ny.gdp.pcap.pp.kd) clear long
If you are still unable to download multiple series then please send us the STATA module version details and the syntax used for retrieving data.
Thanks,