[amibroker] Why Can't I Retrieve SIC number?

[chuckitall59]

I'm sure there's something incredibly simple (and obvious to someone 
else) I'm doing wrong here.  My Explore command:  AddColumn(GetExtraData
("SIC"),"SIC");   results in "Error 5, argument #1 has incorrect type
(the function expects a different argument here)"

OK, so I change "SIC" to "QRS" and it works fine.

So why can't I retrieve SIC numbers?  I use QP with QP Plugin 1.6.0

TIA for any help.

Chuck