I'm trying to use PayPal Website Payments Pro and have setup the Gateway.  When I try to check out to test this, I get a critical error.  The event viewer log is:

AssemblyVersion:7.1.2
PortalID:0
PortalName:myElectrical
UserID:3
UserName:Steven
ActiveTabID:176
ActiveTabName:Store
RawURL:/store/ctl/step2/mid/886
AbsoluteURL:/Default.aspx
AbsoluteURLReferrer:http://myelectrical.com/store/ctl/step2/mid/886
UserAgent:Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)
DefaultDataProvider:DotNetNuke.Data.SqlDataProvider, DotNetNuke
ExceptionGUID:975803f8-88e8-4167-8f9c-f1c28744c62f
InnerException:Object reference not set to an instance of an object.
FileName:
FileLineNumber:0
FileColumnNumber:0
Method:Smith.DNN.Modules.BuyNow.Step2.ibNext_Click
StackTrace:
Message:
DotNetNuke.Services.Exceptions.PageLoadException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object. at Smith.DNN.Modules.BuyNow.Step2.ibNext_Click(Object sender, EventArgs e) at System.Web.UI.WebControls.LinkButton.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---
Source:
Server Name: hvps151

After checking other posts, I have also confirmed that the site is set to Full Trust.
I'm using Smith Cart 5.62.0 (trail version) and DNN 07.01.02.