Error in eCart code

The code

<%
if (cStr(cStr(Request.Form("billingcountry"))) <> "") then
Session("TaxRate") = "" & cStr(cStr(Request.Form("billingcountry"))) & ""
end if
%>

sets Session("TaxRate") to a string from the database, it is either 0.19 or 0, I have verified it doing this on ordersummary.asp page where tax and shipping is calculated so i know the Session is working correctly at that point. When i then click to go from the ordersummary.asp page to the paymentdetails.asp thats when the error is shown even though i never change the value of the Session:

Microsoft VBScript runtime error '800a000d'
Type mismatch: '[string: "Germany"]'
/dmbc/WA_eCart/dmbp_VB.asp, line 260

I can supply more files if you need them.

Regards