Walmart responded and told me how to fix it
This is what Walmart told me and it worked. I was finally able to place my order yesterday morning and I even placed an order again today.
"We have accessed your account and upon duplicating the error you mentioned, we were unable to find any technical problems that might affect the availability of our Web site. Before you try to access your account again, please check your Web browser's settings to make sure that cookies, Java Applications and JavaScript are enabled on your computer. We also recommend you to delete your cookies by following theses steps below and with these features enabled from your Web browser, you should have no problem placing your order.
1. Click on "Tools" in the top menu bar
2. Click on "Internet Options"
3. Click on "Delete Cookies" and "Delete Files"
4. Click "OK" to exit out of the Tools menu"