I have an FXCM Account and in MetaTrader 4 i can list the available symbols. There under USD Shares i find stock CFDs where "EBAY.us" is one of them. The asset "EBAY.us" is also in the FXCM reference.

I can place an order in MetaTrader 4 just fine for this asset in my real account.

Zorro also finds the symbol and actually starts downloading the price history data but crashes in the process. If the symbol data was not available or the data can not be downloaded as is the case for a demo account I get the error "Error 053: XXX unavailable at this time".

Here is the FXCM reference (you will find EBAY.us in it):
Internationale Aktien handeln
Share Liste

The script is able to buy an EBAY share via the MT4 Bridge, so this is definitely a bug with Zorro or the FXCM Api.