Index Out fo Range

I have the code below :  the aceinquiry.getAccount method only return a string, but I get the error further below. I'm using UFT 12.02.  So far it has proven sorry for using the DotNetFactory.

Set aceinquiry = DotNetFactory.CreateInstance("ACE_Inquiry.Inquiry""C:\\DLLs\\ACE_Inquiry.dll")
Set mylist = DotNetFactory.CreateInstance("System.Collections.ArrayList")
mylist = aceinquiry.GetAccount("4000000445""accountOptions")   
mylist = Split(stringVal, ",")

Error:External object ACE_Inquiry.Inquiry::GetAccount has thrown the following exception:
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Line (8): "mylist = aceinquiry.GetAccount("4000000445", "accountOptions")".