OK, I think I'm getting somewhere....I've given up on the USPS issue, and will tackle that issue at a later time (went ahead and purchased a third-party plug-in, and works). However, now I'm getting the following message when processing the checkout page:
Error Code: 10501
Severity Code: Error
Short Err Mssg: Invalid Configuration
Long Err Mssg: This transaction cannot be processed due to an invalid merchant configuration.
Full Request: <developertestaccount><developerpsswd><developersignature>2.20Sale838.7517.5075071.25WebAssist.eCartASP.Pro.DP30AK-Contracts50130AK-Torts544120CA-Cal Essay Package65Visa4169510120000580042019verifiedIanChestnutsuppor_1240834701_per@ivcpro.comUS
88282 Someplace St.Los AngelesCAUSUS90089832-563-0905
Full Response: <developersignature>2009-04-28T18:36:04ZFailuree2a33ad3b1be8Invalid ConfigurationThis transaction cannot be processed due to an invalid merchant configuration.10501Error2.20892334838.75
Do you see anything in here that will help point me in the right direction?