Uninformative error message when range or sheet name not found

[4er4er4er]

The following example looks for costSheet in the spreadsheet file notfind.xlsx:

set PROD;
param cost {PROD};

table costTab IN "amplxl" "notfind.xlsx" "costSheet": [PROD], cost;
read table costTab;

But if costSheet does not exist, the following general error message is displayed:

	Error reading table costTab with table handler amplxl:
	could not find table

This confuses users because "table" refers both to the AMPL table and to a table of data in the spreadsheet. Instead, amplxl should identify the problem more specifically; for example, the error message could be

	could not find a range or sheet named costSheet

The same comments apply to

table costTab IN "amplxl" "notfind.xlsx": [PROD], cost;

when no range or sheet named costTab can be found.

[nfbvs]

Fixed in 44ff3c7