I'm receiving "The following errors have occurred.   (13) The merchant login ID or password is invalid or the account is inactive." from https://secure.authorize.net/gateway/transact.dll when placing my order for Guide9 from your page http://www.projectpluto.com/guide9a.htm and clicking the 'Continue' button. 

After I filled the first page entering the security question in Upper/Lower case and clicked the Continue button is when the above error msg appears.  Help…joe  :)

PS:  Clicking on your Link for "Click here for the order form for payment via cash, check, or money order.", (http://www.projectpluto.com/orderfm.htm) that page cannot be found.

"May You Go Among The Imperishable Stars"

Joe Mize, www.cav-sfo.com

Chiefland Astronomy Village, FL

StarFields Observatory, (SFO)